______ summer nights, we often go to sleep ______ the window open.
The first thing ______my brother is going to do this afternoon is to write a letter.
If you have lost a library book, you have to ___it.
Robert with his two kids ______to the beach for vocation every year.
--- Sam, do you know when Alice ______to my party ? ---I think she will come when she ______free .
We have two rooms ________, but I can’t decide ___________.