急性心肌梗死发生心脏破裂最常见的先兆是（）
A.呼吸困难
B.大汗
C.胸痛
D.晕厥
E.休克
参考答案：C
—Did you spend a lot of time looking for the missing child?
—________. It took us a long time, but luckily we found him.
A．My pleasure
B．Absolutely
C．Not at all
D．Don’t mention it
文件型病毒的传染对象主要是（）类文件。
A.DOC
B.PRG
C.DBF
D.COM和.EXE.BAT
