Some people fear that ______ air pollution may bring about changes in ______ weather around the world.

About of the students like keeping diaries in English in our class.

The river is very long and it is about.

Can I join their club?– I am afraid you will be refused __________ you’ve passed all their tests.

Jack, when shall we go to visit Mr. Smith? – It’s up to him. We’ll go to see him whenever _______.