20. Robert and his songs ________ were famous in the United States are also popular in China.
A. which
B. who
C. that
D. as
下列关于西周的婚姻与继承制度的说法中，哪一项是不正确的( )
A. 一夫一妻制，同姓不婚，父母之命、媒妁之言，这是西周时期婚姻缔结的基本原则
B. 在西周时期，如果一个婚姻没有经过“纳采、问名、纳吉、纳征、请期、亲迎”这六种程序，那么该婚姻不能有效成立
C. “七出、三不去”是西周时期关于婚姻解除的制度
D. 在继承制度方面，西周时期实行的是长子继承制
About two thirds of the population in China ______ in the countryside.
A. is still living
B. were still living
C. was still living
D. are still living
与子宫颈癌发生关系密切的病毒是
A. EB病毒
B. 人乳头瘤病毒
C. 柯萨奇病毒 D．巨细胞病毒
D. 疱疹病毒
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