What role does a teacher play in the following activity?
 
T: Do you have any hobbies?
 
S: Yes, I like singing and dancing.
 
T: Uhm, and.?
 
S: I also collect coins.
 
T: Oh, really, how many..have you already.. collected?
 
A、Controller
B、Assessor
C、Organizer
D、Prompter

A.单叶双曲面B.双叶双曲面C.双曲抛物面D.椭球面

单项选择题 A. 单叶双曲面 B. 双叶双曲面 C. 双曲抛物面 D. 椭球面

5. (1) That is not suitable for the people using the wo...

单项选择题5. (1) That is not suitable for the people using the work-from-home way to instead the working in the company. (2)Just like our president Zhu said, human nature is always important in each time. (3)That is home alone, friendship away. 
判断：句（1）切题。
A、正确
B、错误

链霉素是由以下哪个类群的菌产生的A．细菌 B．真菌 C．放线菌 D．病毒

单项选择题链霉素是由以下哪个类群的菌产生的