用介词in或on填空(每空一词)
The dog can walk____ two legs. It can dance, too.

They can also remember places        food and water.

I am sure you know the difference        “look for”        “find”.

The teacher stood        the window, watching the boys playing outside.

I wrote         my brother last Saturday, but I still don’t hear        him now.

We shouldn’t(不应该) go to school       breakfast. It’s bad for our health.

The old man is a good swimmer, and he often swims       the river after supper.

We can get fresh water from rain, from rivers, or from          the ground.

—Why are you standing there, Maggie?
—I can’t see the blackboard clearly. Two tall boys are sitting         me.

—I left(遗忘) my keys in the room yesterday. I had to get in        the window.
—It’s dangerous(危险的) to do that.