Gun control is a subject ______ Americans have argued for a long time.

单项选择题Bats are surprisingly long-lived creatures, some ______ a life span of around 20 years.

单项选择题As a salesman, he works on a (an) ______ basis, taking 10% of everything he sells.

单项选择题I'm not quite sure how to get there. I'd better______a map.

单项选择题—I'm going to study engineering in Tsinghua University tomorrow. —______.

单项选择题______被认为是教育心理学的创始人。

单项选择题—You haven't been to Beijing, have you — ______. And how I wish to go there again!

单项选择题According to the United States Constitution, the legislative power is invested in ______.

单项选择题“道之所存，师之所存也”，这体现了教师的( )。

单项选择题（）是英语课程的出发点和归宿。

A．知识的传授
B．学生的发展
C．语言的运用
D．习惯的养成

单项选择题You () the project by now.

A. are supposed to finish
B. supposed to finish
C. are supposed finishing
D. are supposed to have finished