--Do you think the math problem was difficult?--Yes. But I could ________ make it.
-___ __ you ____ _ your drawing? -Not yet. It will be done in a few minutes.
The teacher told us the earth ________ around the sun.
He’s been in China for two years. And he’s used to _______ in China.
_______ his help, we finished the work on time.
-___ __ have you worked? -Since 2 pm.