— Can you give me the right answer?—Sorry, I ______ . Would you repeat that question?

—Has your son come back from abroad for the winter vacation?—Yes. But he stayed at home for only a week. Now he      back to college.

--- Julia hurt her back when she fell, and she is now in hospital. --- Oh, really? I _____ know. I _____ go and visit her.

---Don't put the waste on the ground. ---Oh, I'm very sorry. I ________ the dustbin（垃圾箱） there. 

“I suppose you _________ that report yet?” “I finished it yesterday, as a matter of fact.”