窄小场所下的起重吊装作业有（）种基本情况。
A.2种
B.3种
C.4种
D.5种
参考答案：A
有关二尖瓣狭窄，下列哪项对诊断最有意义（）
A.体检听诊心尖部舒张期隆隆样杂音
B.X线检查
C.心电图
D.超声心动图检查
E.询问病史
He is not tired. He_____ have a rest. [ ]
A. needs not
B. not need
C. needn't to
D. doesn't need to
