第33题: [单项选择]"子痫"发生的主要机制是 A. 妊娠腹痛 B. 异位妊娠 C. 胎动不安 D. 胎漏 E. 小产 参考答案:A
第34题: [单项选择]______ percentage of working women in the United States has doubled since 1940 has been the result of both economic and social factors. A. The B. That the C. There is the D. It is the 参考答案:B 答案解析:That引导主语从句作“has been the result”的主语。percentage需有定冠词修饰。