子宫肌瘤不孕的原因是()
A．肌瘤阻碍受精卵着床
B．宫腔变形输卵管入口受阻
C．子宫肌瘤伴随卵巢功能失调
D．肌瘤接近浆膜层
参考答案：A, B, C
—Tom, your foreign teacher speaks Chinese fluently!
—Oh, she has lived in China for six years, otherwise she _______ such good Chinese.
A．didn’t speak
B．would not have spoken
C．would not speak
D．hadn’t spoken
甲是乙企业的销售人员，随身携带盖有乙企业公章的空白合同书，便于随时对外签约。后甲因收取回扣被乙企业除名，但空白合同书未收回。甲以此合同书与丙签订购销协议，该购销协议的效力应如何认定？（）
A.不成立
B.无效
C.效力待定
D.有效
