Each year __________ fishes are killed by the polluted water and many people are made sick by the polluted air .—-So we should do something to stop it .

It is a good habit of ______ to read a few lines before going to bed.

Stephen Hawking thinks _______ important to have hope in bad situation.

Were you sick after six hours’ journey ?——Of course. I __________ quickly as soon as it stopped.

What do you usually do a rainy day. [ ]