House owners        keep their gardens in a neat and orderly state according to the regulations.

When we were in the college, we       stay in the library, devoting ourselves to books.

I ______ tell you with certainty that he won’t be able to finish it before the deadline. 

—Have you seen Maragaret? The boss is looking for her everywhere.—She________the train, otherwise she would have arrived here by now.

–Look at that girl! Is it Susan? --No, it _______ be her. She went to her hometown just now.