The retired teacher is said to have returned from the USA, where he ______ by some of his old students

________ your homework yet– Not yet. I _______ it.

If you don’t ______ , you will succeed at last.

Mary，I don’t know ____ you can come tomorrow morning. —No problem! I’ll be here _____I’m free then.

There is____with my computer. Can you help me mend(修理) it