练习：
1.A sweet B sound C bad D enough
2.A checking B sharing C continuing D meeting
3.A lovely B likely C fondly D finely
4.A for B at C in D with
5.A at least B at most C at last D at first
6.A ability B health C thinking D life
7.A experiment B reform C idea D way
8.A repeat B improve C change D leave
9.A work B mistakes C energy D time
10.A never B seldom C too D also
11.A ready B good C sleepy D awake
12.A all B few C any D nothing
13.A unless B while C until D during
14.A would B may C might D should
15.A helpful B difficult C easy D happy