室上性心动过速最多发生于：（）
A.无器质性心脏病
B.急性心肌梗死
C.洋地黄中毒
D.低血钾
E.甲状腺功能亢进
参考答案：A
When we meet some new words, we’d better in a dictionary.
A．look them up
B．look them out
C．look out them
D．look up them
