Choose the correct answer
13. You should sleep............7 to 8 hours a day
A.at B.about C.with D.during
14. There should be a balance.......... work or study and leisure
A.between B.in C.at D.from
15.stop smoking because it is harmful....health
A.of B.for C.at D.to
A.at B.about C.with D.during
14. There should be a balance.......... work or study and leisure
A.between B.in C.at D.from
15.stop smoking because it is harmful....health
A.of B.for C.at D.to