大量咯血常见于（）
A.肺梗死
B.白血病
C.急性左心衰竭
D.肺脓肿
E.支气管肺癌
参考答案：D
In April,thousands of holidaymakers remained _____ abroad due to the volcanic ash cloud. [ ]
A. sticking
B. stuck
C. to be stuck
D. to have stuck
DR的种类中不包括
A．直接型B．间接型C．多丝正比电离室型D．CCD型E．光激励发光型
