空压机每运行（）小时检查气缸、排气阀一次。
A.50～100
B.100～150
C.150～200
D.200～250
参考答案：B
Mr. Smith couldn’t open the door because his naughty boy _______ it from the inside
A．would lock
B．was locking
C．has locked
D．had locked
清热燥湿又能退虚热的药物
A．黄芩B．黄连C．黄柏D．苦参E．龙胆草
