Through和across都是介词，表示通过或横跨某物或某地，但在使用上有些许的差异。

Through通常用于表示穿过或通过某个位置或物体的内部。例如，Examples:

- She walked through the park.

- The water flowed through the pipe.

- He read through the whole book.

而Across则通常用于表示横跨某个区域或物体的表面。例如，

- She walked across the bridge.

- The plane flew across the ocean.

- There's a path across the field.

除此之外，Through还可以表示“贯穿，经过”等意思。例如：

- I'm going through a difficult time right now.

- The road through the mountains was treacherous.

- The teacher went through each question one by one.

而Across则可以表示“在对面”等意思。例如：

- I saw him across the street.

- There's a store across from the movie theater.

使用上要根据具体情况选择正确的介词。如果是通过物体的内部，则应使用Through；如果是横跨物体的表面，则应使用Across。

"Through"和"across"都是表示通过或穿过某个位置或场景的动词，但它们的具体用法和含义略有不同。

"Through"通常表示通过某物或环境内部，沿着某个路径穿过去。例如：

- I walked through the park to get to the other side.

- The water flowed through the pipes and into the house.

"Through"还可以表示透过某个障碍物的物质通过。例如：

- I can see through the window that it's raining outside.

- The sun shone through the clouds.

"Through"还可以表示完成某事，表明持续到底的状态。例如：

- I made it through the whole book in one day.

- We'll get through this difficult time together.

而"across"则强调横跨某个位置或场景的情况。通常用来描述从一个较低的位置穿越到一个较高的位置，或者穿过较宽的区域。例如：

- The bridge spans across the river.

- We swam across the lake to the other side.

"Across"还可以表示在某个超出感知范围的距离上。例如：

- I heard a loud noise from across the street.

- The store is across town, we'll need to drive there.

"through"和"across"都是表示通过某个位置的动词，但通常用法略有不同，可以根据语境来选择使用。