海湾战争时科威特大量油井的燃烧,对大气造成严重的污染,甚至导致某些地区黑雨的降落,请你分析此黑雨的主要成分是( )
A.二氧化碳
B.炭黑
C.甲烷
D.一氧化碳
答案:B
When father was young, he ______ from morning till night. [ ]
A. was made work
B. was made working
C. made to work
D. was made to work
下列属于儿童佝偻病的临床表现的是( )。
A.胸部肋骨串珠
B.夜惊
C.手足躅
D.出牙晚
E.罗圈腿