以下（）原因可导致合同无效。
A.重大误解
B.显失公平
C.乘人之危
D.中方当事人无对外经营权
参考答案：A, B, C, D
—English has a large vocabulary, _______?
—Yes. Know more words and expressions and you will find _______ easier to read and communicate.
A．hasn't it; it
B．doesn't it; that
C．has it; what
D．does; one
瞳孔缩小可见于（）
A.五风内障
B.杏仁中毒
C.毒蕈中毒
D.川乌中毒
E.有机磷农药中毒
