Is the girl in the red skirt your sister?—No. It _______ be her. She has flown to Australia.

This exercise is ________ difficult ________. [ ]

I don’t think I will win a lottery (彩票) of —Well, ______. Everything can happen.

It’s very ____________ to play ____________ football with them.

Aren’t your parents in Beijing now? —No. They left ____ Shenyang yesterday.[ ]