It has been widely accepted that only when the students take an active part in the class activities _______ the most effective.

Mom, my classmates invited me ________ a field trip. May I go with them —OK.

There ______a number of books in our school library. The number of books ________getting larger than last year.

How can we protect ourselves ________ the earthquake —We should stay calm first.

I’ll_____ going to Scotland until you’re well enough to look after yourself again. [ ]