The leaves are _________ the tree.[ ]
A. on
B. in
C. at
答案:A
Japan’s economy _______ in the past twenty years. No one knows how long it ______ before it regains its increase.
A.has been declining; will be
B.has declined; would be
C.had been in decline; would take
D.was on the decline; will take
诊断闭经时用孕激素试验阴性可以说明( )
A.有排卵B.子宫内膜未受雌激素水平影响C.停经后有出血D.子宫内膜已受雌激素水平影响E.无排卵