以下哪种病原菌引起假膜性肠炎（）
A.破伤风梭菌
B.产气荚膜梭菌
C.肉毒梭菌
D.艰难梭菌
E.酪酸梭菌
参考答案：D
Though he is busy, music has always been _______ his work.
A．as much a part of his life as
B．as a part of his life much as
C．as much as a part of his life
D．so much a part of his life as
在哪种情况下，起落架指示面板上未锁定灯亮？（）
A.起落架在所选位置未锁定
B.起落架重力放出，舱门未关闭
C.起落架正常放出，舱门未锁定
