Although the causes of cancer_____, we do not yet have any practical way to prevent it.
-- ______________, I can make it home by 8:30 when the football game will be on TV. -- Well, it depends on how efficiently you work.
— My God! I haven’t finished my summer homework yet! — ______. The time when you go back to school is two days later.
There are some warnings in some countries ______ over exploitation of underground water has caused the decline of wetland and increase of desertification.
This new English-English dictionary is useful for me. ______, I’ll buy it.
______ what your families said just now, I think, and you will make your own decision.