筛查原发性肝癌简单有效的方法为
A.B超
B.CT
C.AFP
D.MRI
E.同位素
参考答案:C
扇形统计图可以很清楚地表示出______同______之间的关系,______统计图可以清楚看出事物的变化趋势.
________ the morning train, he would not have been late for the meeting.
A.Did he catch
B.should be catch
C.has he caught
D.Had he caught