纵断面设计时，力求纵坡平缓，陡坡宜短，主要是为了（）。
A、汽车保持高速行驶
B、汽车获得较大的动力因数
C、汽车制动
D、以上全正确
参考答案：A
用be动词的适当形式填空。
1. I ______________ Xiao Ming. I ______________ nine years old.
2. Dick ______________ a singer.
3. Excuse me, ______________ you a teacher?
4. Tom and Lucy ______________ good friends. They ______________ in the same class.
5. What day ______________ it today?
6. It ______________ not a penguin (企鹅).
7. These boxes ______________ too heavy for me.
8. There ______________ a tree on the hill.
9. There ______________ many birds in the sky.
10. My name ______________ Martin. I ______________ from Australia.
周期性瘫痪发作期常见的临床表现是（）
A.肢体对称性弛缓性瘫痪
B.病肌饱满坚实
C.腱反射降低或消失
D.手套袜套样感觉障碍
E.尿便功能障碍
