简述反射弧及其结构。
参考答案：执行反射的全部神经结构叫做反射弧。一般包括五部分：感受器、传入神经纤维、中枢、传出神经纤维和效应器。
用括号中所给词的适当形式填空。
1. Tom is much _____than Sam. ( cool )
2. My hair is a little _____than hers. ( short )
3. Pedro is _____than Paul. ( funny )
4. Li Ping is a little_____than me. ( outgoing )
5. Which is_____ in China, tea or coffee? ( popular)
6. Tina is much_____than Tara. ( athletic )
7. Liu Li is a little_____than her sister. ( quiet )
8. Ruth is_____than any other girl in my class. ( serious )
9. Java has _____ hair than Mary. ( curly )
10. Paul is _____than Pedro. ( thin )
工程测量高程控制网等级划分为（）
A.1等
B.2等
C.3等
D.4等
