第33题: [单项选择]下列哪种是被动免疫的生物制品 A. 伤寒菌苗 B. 卡介苗 C. 麻疹疫苗 D. 白喉类毒素 E. 破伤风抗毒素 参考答案:E
第34题: [单项选择]The symbols of mathematics ______we are most familiar are the signs of addition, subtraction, multiplication, division and equality. A. to which B. which C. with which D. in which 参考答案:C 答案解析:该题测试词组的用法和句前带介词的从句用法。本题be familiar with词组中的介词with移到which引导的we are most familiar从句前。familiar之后既能接with