介词表语是指介词后面所跟的名词、代词或动词不定式等，用来说明句子中的主语或宾语的性质、特征、状态、方向等。以下是30个常用的介词表语及其用法。

1. About：关于，对于

He is always talking about his new job.

2. Above：在……之上，超过

The plane flew above the clouds.

3. Across：横跨，穿过

The bridge spans across the river.

4. After：在……之后，追随

After the rain stopped, the sun came out.

5. Against：反对，倚靠

The wall is leaning against the tree.

6. Along：沿着，顺着

We walked along the beach.

7. Among：在……之中，当中

There were many people among the crowd.

8. Around：在……周围，大约

He walked around the park.

9. At：在……处，以……为目标

She is good at math.

10. Before：在……之前，先于

We arrived before the movie started.

11. Behind：在……后面，落后

The car is parked behind the building.

12. Below：在……之下，低于

The temperature is below freezing.

13. Beneath：在……下面，在……之下

The submarine is hidden beneath the water.

14. Beside：在……旁边，与……相比

She sits beside her sister.

15. Between：在……之间，两者之间

The book is between the two lamps.

16. Beyond：在……之外，超出

The view from the mountain top is beyond words.

17. By：靠近，通过，由……完成

The train arrived by the station.

18. Down：向下，沿着，关掉

He walked down the stairs.

19. During：在……期间，经过

She studied hard during the exam week.

20. Except：除了……以外，不包括

Everyone was there except for Tom.

21. For：为了，因为，持续

He works hard for his family.

22. From：从……来，离……远

The train is coming from the station.

23. In：在……中，穿着

She is in the classroom.

24. Inside：在……里面，内部

The cat is inside the box.

25. Into：进入，变成

The water turned into ice.

26. Like：像，例如

She sings like a bird.

27. Near：在……附近，接近

The restaurant is near the park.

28. Of：……的，关于

The color of the sky is blue.

29. Off：离开，关闭

He turned off the TV.

30. On：在……上，关于

The book is on the table.

以上是30个常用的介词表语及其用法，掌握这些介词的用法可以帮助我们更好地理解和使用英语。