No one has yet succeeded in explaining the ________of how life began.
A.puzzle B.problem C.cause D.reason
________ what way did you work out the Maths _____?
A.In, problem B.By, problem C.In, question D.By, question
Work is hard. ________ trying and you'll be successful in the end.
A.Give up B.Keep on C.Give in D.Turn on
The whole street is full of rubbish and it smells ________.
A.badly B.strange C.terrible D.wonderful
You'd better ________ too much time ________ football.
A.not spend, on B.not spend, play C.not to spend, on D.don't spend, for
The price of the coat is so ________that I can't buy it.
A.expensive B.valuable C.low D.high
