Some people fear that ________ air pollution may bring about changes in _______ weather around the world.
I was about to get on the bus _________someone called.
It was Mr Green _______ looked after my grandmother when I was on business.
Don’t ________when you are in trouble, you should be brave.
The old man was deeply moved by the nurses who ______him while he was sick.
We should take ______of this opportunity to make a good impression on them.