根据句意，用所给单词的适当形式填空。

小题1:How happy we were to see the safe ____________ (arrive) of all the Chinese fishermen!

小题2:The ____________ (two) Summer Youth Olympic Games will be held in Nanjing in August,2014.

小题3:Compared with the young，People in the old days were living more ____________ (comfortable)

小题4:The ____________ (strict) his teacher is with him, the more progress he will make.

小题5:Children under 12 can’t be left at home by ___________ (them) in some states of America.

X线照片锐利度的叙述，错误的是（）

A.半影导致影像的模糊

B.半影越大影像锐利度越差

C.肢-片距越大影像锐利度越差

D.焦-片距离大半影小影像锐利

E.阴极端影像锐利度大于阳极端