函数f（x）=log2（2-x）的单调减区间是______．

保险利益消失，保险合同随之失效。()

What disappointed us was that their determination finally        .[      ]

A. gave off

B. gave out

C. gave up

D. gave in

在一定温度下催芽，当种子有（）左右“露白”时停止催芽，等待播种。

A.25%

B.35%

C.66%

D.95%

“Public Opinion”

锅炉凝渣管又叫（）管。