she is not so cheerful        she used to be?

It was          back home after the experiment.

It was not until I was injured in a car accident ______ the real American society．

It was at 10 o’clock last night __________ the visitors finally arrived at Pudong International Airport.

It was from only a few supplies that she had bought in the village     the hostess cooked such a nice dinner.

It’s _____ you do today that will make a difference in your life tomorrow.

I really don’t know _________ I had my money stolen.

It was because I was ill ________ I didn’t go to school.

It was not until 1911, _______ the first vitamin was identified, _______ people realized the importance of it．

it was because of his kind nature _______I fell in love with Peter.