---I called you yesterday evening, but there was no answer.　　　　  ----- Oh, I’m sorry. I _____ dinner at a restaurant at that time.

There ______ great changes in our hometown in the past fifteen years.

------- _______ you _______ the book ______ to the library yet. ------ Yes. I have.

Mr. and Mrs. Black ______ back _________.

——Why is the classroom so dirty?——Sorry, Sir. It _____ yesterday. We forgot to do it.

—Do you __________ an American friend?—No, I don’t. But my sister __________ one.

While Suzy ______ on the sofa, the phone rang.

－______ he______ at this school last term?－Yes, I think so.

－Why not go to see the dolphin show with me?－Because I _______ it.

－ Is your father in?－ No, he ______ for three hours.

—Where is Mr. Green now ? I haven’t seen him for a few days .—He _____ to Hong Kong .

My brother _______ an English teacher in ten years.

What ____ you ______ at this time yesterday? 

There will _________ robots in people’s homes.

His mother ____ in a village five years ago.

I am very sad that I ______ many chances in the last few years.

You shouldn’t ________ here . The baby _____.

I think China ______ a much stronger and more beautiful country in 2050.

---Don’t play soccer in the street. --- Sorry, I        do that again.

While the boy ______ down the street, the UFO _____ .