Ⅰ.单句语法填空：根据句意，在空线处填上适当的关系代词。
1．(2019·天津和平区高三年级质量调查)The government placed restrictions on the numbers of foreign cars ________ could be imported.
答案：that/which 设空处引导限制性定语从句，先行词foreign cars指物，设空处在从句中充当主语，故用that/which。
2．(2019·天津东丽区高三毕业班质量监测)This semester our school offers many optional courses for the students, each of ________ appeals to many students.
答案：which 此处为“介词＋关系代词”引导的非限制性定语从句，先行词是courses，指物，介词of后面的关系代词用which。
3．(2019·湖南五市十校教研教改共同体高三联考)This informs the brain about the location of the touch, the amount of force used, and the speed at ________ it was used.
答案：which 此处为“介词＋关系代词”引导的定语从句，先行词是speed，指物，介词at后面的关系代词用which。
