—Nowadays a growing number of people go to work by bike.—Bicycling is good exercise;________it doesn't pollute the air.
—Do you know why Lisa cried in class?—I don't know and I don't ________.
Many teens don't get enough sleep because they have too much homework to do, which ________ them up at night.
Freddy made up his mind to enjoy his singing and to________ as many happy experiences as he could.
The Chinese government has overcome problems of population and economy to ________ its “nine years of compulsory education”.
—How did you find the film The Flowers of War? —It's very moving. I couldn't ________ my tears.