We should do everything we can _______ the birds _______ danger.

John, you _______ stay out late. Your mother will worry about you.

The apartment in the city center is so expensive that it can only be ________ to the rich people.[ ]

The use of computers has made ______ possible for more people to work at home.

Whose pen is this — Oh, it’s_____. I was looking for it everywhere.