diff --git a/README.md b/README.md
index 27e253a..beb4dd6 100644
--- a/README.md
+++ b/README.md
@@ -32,7 +32,7 @@ By harnessing the capabilities of Executor Engine, users can effortlessly constr
 
 + 📚 Support multiple job types
   * `LocalJob`, `ThreadJob`, `ProcessJob`, `DaskJob`
-  * Extend job types: `SubprocessJob`, `WebappJob`
+  * Extend job types: `SubprocessJob`, `WebappJob`, `CronJob`
 + 🔧 Job management
   * Job dependency management.
   * Job status: Pending, Running, Done, Failed, Cancelled.
diff --git a/docs/api-reference/condition.md b/docs/api-reference/condition.md
index 6f06f8e..3d10c82 100644
--- a/docs/api-reference/condition.md
+++ b/docs/api-reference/condition.md
@@ -15,22 +15,57 @@
     options:
         show_root_heading: true
 
-::: executor.engine.job.condition.AfterTimepoint
+::: executor.engine.job.condition.Combination
     handler: python
     options:
         show_root_heading: true
 
-::: executor.engine.job.condition.Combination
+::: executor.engine.job.condition.AllSatisfied
     handler: python
     options:
         show_root_heading: true
 
-::: executor.engine.job.condition.AllSatisfied
+::: executor.engine.job.condition.AnySatisfied
     handler: python
     options:
         show_root_heading: true
 
-::: executor.engine.job.condition.AnySatisfied
+::: executor.engine.job.condition.TimeCondition
+    handler: python
+    options:
+        show_root_heading: true
+
+::: executor.engine.job.condition.EveryPeriod
+    handler: python
+    options:
+        show_root_heading: true
+
+::: executor.engine.job.condition.AfterClock
+    handler: python
+    options:
+        show_root_heading: true
+
+::: executor.engine.job.condition.BeforeClock
+    handler: python
+    options:
+        show_root_heading: true
+
+::: executor.engine.job.condition.AfterWeekday
+    handler: python
+    options:
+        show_root_heading: true
+
+::: executor.engine.job.condition.BeforeWeekday
+    handler: python
+    options:
+        show_root_heading: true
+
+::: executor.engine.job.condition.AfterTimepoint
+    handler: python
+    options:
+        show_root_heading: true
+
+::: executor.engine.job.condition.BeforeTimepoint
     handler: python
     options:
         show_root_heading: true
diff --git a/docs/api-reference/extend_job.md b/docs/api-reference/extend_job.md
index 258c604..69e480a 100644
--- a/docs/api-reference/extend_job.md
+++ b/docs/api-reference/extend_job.md
@@ -8,4 +8,15 @@
 ::: executor.engine.job.extend.WebappJob
     handler: python
     options:
-        show_root_heading: true
\ No newline at end of file
+        show_root_heading: true
+
+::: executor.engine.job.extend.SentinelJob
+    handler: python
+    options:
+        show_root_heading: true
+
+::: executor.engine.job.extend.CronJob
+    handler: python
+    options:
+        show_root_heading: true
+
diff --git a/docs/getting-started.md b/docs/getting-started.md
index 8a1c916..23dd649 100644
--- a/docs/getting-started.md
+++ b/docs/getting-started.md
@@ -45,8 +45,13 @@ engine = Engine()
 def add(a, b):
     return a + b
 
+async def add_async(a, b):
+    # async function can also be used as the job function
+    await asyncio.sleep(1.0)
+    return a + b
+
 async def main():
-    job1 = ProcessJob(add, args=(1, 2))
+    job1 = ProcessJob(add_async, args=(1, 2))
     job2 = ProcessJob(add, args=(job1.future, 4))
     await engine.submit_async(job1, job2)
     await engine.join()
@@ -96,73 +101,6 @@ They are executed by different backends and suitable for different scenarios.
 | `ProcessJob` | `executor.engine.backend.process` | CPU-bound tasks |
 | `DaskJob` | `executor.engine.backend.dask` | Distributed tasks |
 
-### Extend job types
-
-There are two extend job types:
-[`SubprocessJob`](api-reference/extend_job.md#executor.engine.job.extend.SubprocessJob)
-and
-[`WebappJob`](api-reference/extend_job.md#executor.engine.job.extend.WebappJob)
-. They are used to execute shell commands and launch web applications.
-The extend job types can based on the job types above(`LocalJob`, `ThreadJob`, `ProcessJob`, `DaskJob`).
-
-#### SubprocessJob
-
-[`SubprocessJob`](api-reference/extend_job.md#executor.engine.job.extend.SubprocessJob)
-is a job type for executing shell commands.
-`SubprocessJob` accept a shell command as its argument. It will execute the command in a subprocess:
-
-```python
-from executor.engine import Engine
-from executor.engine.job.extend import SubprocessJob
-
-job = SubprocessJob(
-    "python -c 'print(1 + 2)'",
-)
-
-with Engine() as engine:
-    engine.submit(job)
-    engine.wait_job(job)
-```
-
-
-#### WebappJob
-
-[`WebappJob`](api-reference/extend_job.md#executor.engine.job.extend.WebappJob) 
-is a job type for launching a web application.
-It can accept a function with `ip` and `port` as arguments:
-
-```python
-from executor.engine import Engine
-from executor.engine.job.extend import WebappJob
-from http.server import HTTPServer, SimpleHTTPRequestHandler
-
-def run_simple_httpd(ip: str, port: int):
-    server_addr = (ip, port)
-    httpd = HTTPServer(server_addr, SimpleHTTPRequestHandler)
-    httpd.serve_forever()
-
-with Engine() as engine:
-    job = WebappJob(run_simple_httpd, ip="127.0.0.1", port=8000)
-    engine.submit(job)
-    print("Open your browser and visit http://127.0.0.1:8000")
-    engine.wait()
-```
-
-`WebappJob` can also accept a command template as its argument:
-
-```python
-from executor.engine import Engine
-from executor.engine.job.extend import WebappJob
-
-with Engine() as engine:
-    job = WebappJob(
-        "python -m http.server -b {ip} {port}",
-        ip="127.0.0.1", port=8000)
-    engine.submit(job)
-    print("Open your browser and visit http://127.0.0.1:8000")
-    engine.wait()
-```
-
 ### Conditional job execution
 
 After another job:
@@ -284,6 +222,42 @@ with Engine() as engine:
     engine.wait()
 ```
 
+##### Syntactic sugar for condition combination
+
+You can use `&` and `|` to combine conditions:
+
+```python
+from executor.engine import Engine, ThreadJob
+from executor.engine.job.condition import AfterAnother
+import time
+
+s = set()
+
+def sleep_and_add_1(t: int):
+    time.sleep(t)
+    s.add(t)
+
+def has_two_elements():
+    print(s)
+    assert len(s) == 2
+
+with Engine() as engine:
+    job1 = ThreadJob(sleep_and_add_1, args=(1,))
+    job2 = ThreadJob(sleep_and_add_1, args=(2,))
+    job3 = ThreadJob(sleep_and_add_1, args=(3,))
+    job4 = ThreadJob(
+        has_two_elements,
+        condition=(
+            (
+                AfterAnother(job_id=job1.id) &
+                AfterAnother(job_id=job2.id)
+            ) |
+            AfterAnother(job_id=job3.id)
+        )
+    )
+    engine.submit(job4, job3, job2, job1)
+    engine.wait()
+```
 
 #### Custom condition
 
@@ -319,6 +293,123 @@ with Engine() as engine:
     engine.wait()
 ```
 
+### Extend job types
+
+There are 4 extend job types:
+[`SubprocessJob`](api-reference/extend_job.md#executor.engine.job.extend.SubprocessJob),
+[`WebappJob`](api-reference/extend_job.md#executor.engine.job.extend.WebappJob)
+[`SentinelJob`](api-reference/extend_job.md#executor.engine.job.extend.SentinelJob)
+[`CronJob`](api-reference/extend_job.md#executor.engine.job.extend.CronJob)
+
+They are used to execute shell commands, launch web applications
+and schedule jobs based on time.  The extend job types can based on the job types above(`LocalJob`, `ThreadJob`, `ProcessJob`, `DaskJob`).
+
+#### SubprocessJob
+
+[`SubprocessJob`](api-reference/extend_job.md#executor.engine.job.extend.SubprocessJob)
+is a job type for executing shell commands.
+`SubprocessJob` accept a shell command as its argument. It will execute the command in a subprocess:
+
+```python
+from executor.engine import Engine
+from executor.engine.job.extend import SubprocessJob
+
+job = SubprocessJob(
+    "python -c 'print(1 + 2)'",
+)
+
+with Engine() as engine:
+    engine.submit(job)
+    engine.wait_job(job)
+```
+
+
+#### WebappJob
+
+[`WebappJob`](api-reference/extend_job.md#executor.engine.job.extend.WebappJob) 
+is a job type for launching a web application.
+It can accept a function with `ip` and `port` as arguments:
+
+```python
+from executor.engine import Engine
+from executor.engine.job.extend import WebappJob
+from http.server import HTTPServer, SimpleHTTPRequestHandler
+
+def run_simple_httpd(ip: str, port: int):
+    server_addr = (ip, port)
+    httpd = HTTPServer(server_addr, SimpleHTTPRequestHandler)
+    httpd.serve_forever()
+
+with Engine() as engine:
+    job = WebappJob(run_simple_httpd, ip="127.0.0.1", port=8000)
+    engine.submit(job)
+    print("Open your browser and visit http://127.0.0.1:8000")
+    engine.wait()
+```
+
+`WebappJob` can also accept a command template as its argument:
+
+```python
+from executor.engine import Engine
+from executor.engine.job.extend import WebappJob
+
+with Engine() as engine:
+    job = WebappJob(
+        "python -m http.server -b {ip} {port}",
+        ip="127.0.0.1", port=8000)
+    engine.submit(job)
+    print("Open your browser and visit http://127.0.0.1:8000")
+    engine.wait()
+```
+
+#### CronJob
+
+[`CronJob`](api-reference/extend_job.md#executor.engine.job.extend.CronJob)
+is a job type for scheduling jobs periodically.
+It should be used with different `TimeCondition` for different scheduling strategies. For example:
+
+```python
+from executor.engine import Engine
+from executor.engine.job.extend.cron import (
+    CronJob, every,
+    hourly, daily, weekly,
+    after_clock, between_clock,
+    after_weekday,
+)
+
+
+def do_something():
+    print("hello")
+
+
+with Engine() as engine:
+    # will run the function every 10 seconds
+    job1 = CronJob(do_something, every("10s"))
+    # will run the function every minute
+    job2 = CronJob(do_something, every("1m"))
+    # will run the function every hour
+    job3 = CronJob(do_something, hourly)
+    # will run the function every day at 12:00
+    job4 = CronJob(do_something, daily & after_clock("12:00"))
+    # will run the function every week on Monday at 12:00
+    job5 = CronJob(
+        do_something,
+        weekly & after_weekday("Monday") & after_clock("12:00"))
+    # will run the function every 5min at the night
+    job6 = CronJob(do_something, every("5m") & between_clock("18:00", "24:00"))
+    engine.submit(job1, job2, job3, job4, job5, job6)
+    engine.wait()
+```
+
+See [CronJob](api-reference/extend_job.md#executor.engine.job.extend.CronJob) for more details.
+
+!!! info
+    `CronJob` is a special kind of
+    [`SentinelJob`](api-reference/extend_job.md#executor.engine.job.extend.SentinelJob),
+    `SentinelJob` is a more general kind of job, it will be
+    submit other jobs when the condition is satisfied.
+
+
 ### Generator support
 
 `executor.engine` supports generator job, which is a special job that returns a generator.
diff --git a/executor/engine/__init__.py b/executor/engine/__init__.py
index 41de325..713a802 100644
--- a/executor/engine/__init__.py
+++ b/executor/engine/__init__.py
@@ -1,7 +1,7 @@
 from .core import Engine, EngineSetting
 from .job import LocalJob, ThreadJob, ProcessJob
 
-__version__ = '0.2.9'
+__version__ = '0.3.0'
 
 __all__ = [
     'Engine', 'EngineSetting',
diff --git a/executor/engine/job/condition.py b/executor/engine/job/condition.py
index b2c3bed..47f62da 100644
--- a/executor/engine/job/condition.py
+++ b/executor/engine/job/condition.py
@@ -187,7 +187,7 @@ class EveryPeriod(TimeCondition):
     """
     period_str: str
     last_submitted_at: T.Optional[datetime] = None
-    immediate: bool = True
+    immediate: bool = False
 
     def satisfy(self, _) -> bool:
         period = _parse_period_str(self.period_str)
diff --git a/executor/engine/job/extend/__init__.py b/executor/engine/job/extend/__init__.py
index 1ef9379..5d2fd17 100644
--- a/executor/engine/job/extend/__init__.py
+++ b/executor/engine/job/extend/__init__.py
@@ -1,5 +1,7 @@
 from .subprocess import SubprocessJob
 from .webapp import WebappJob
+from .sentinel import SentinelJob
+from .cron import CronJob
 
 
-__all__ = ["SubprocessJob", "WebappJob"]
+__all__ = ["SubprocessJob", "WebappJob", "SentinelJob", "CronJob"]
diff --git a/executor/engine/job/extend/cron.py b/executor/engine/job/extend/cron.py
index 7648954..dee4a7b 100644
--- a/executor/engine/job/extend/cron.py
+++ b/executor/engine/job/extend/cron.py
@@ -13,8 +13,8 @@
 
 every = EveryPeriod
 daily = EveryPeriod("1d")
+weekly = EveryPeriod("7d")
 hourly = EveryPeriod("1h")
-monthly = EveryPeriod("1m")
 
 before_clock = BeforeClock
 after_clock = AfterClock
diff --git a/executor/engine/job/extend/sentinel.py b/executor/engine/job/extend/sentinel.py
index 8d663a9..0547bec 100644
--- a/executor/engine/job/extend/sentinel.py
+++ b/executor/engine/job/extend/sentinel.py
@@ -43,7 +43,7 @@ def SentinelJob(
     else:
         base_class = job_type
 
-    async def submitter(__engine__: "Engine"):
+    async def sentinel(__engine__: "Engine"):
         while True:
             if sentinel_condition.satisfy(__engine__):
                 job = base_class(func, **attrs)
@@ -51,7 +51,7 @@ async def submitter(__engine__: "Engine"):
             await asyncio.sleep(time_delta)
 
     sentinel_job = LocalJob(
-        submitter,
+        sentinel,
         **sentinel_attrs
     )
     return sentinel_job