The old scientist devoted most of his time ___________ the space science.

Please make a model plane and then ___________ it red.

—I’m sorry I ________ my exercise book at home this morning.—It doesn’t matter. Don’t forget ________ it here this afternoon.

Listen! The little girl ____ a song over there 在那边. She ____songs there every Sunday morning.

The students_____ until the heavy rain stopped.