胚眼由下列哪些发育而成（） A.神经外胚叶 B.脑神经嵴细胞 C.表皮外胚叶 D.中

规定向东为正，那么向西走5千米记为_______千米．

人误服重金属盐中毒后．为了减轻毒性．可服用下列物质中的[ ]

A．水  

B．食盐水  

C．鸡蛋清  

D．肥皂水

— _____ to say good-bye, Tony. I'm catching the 11:00 train.

— Then take care of yourself and don't forget to keep in touch. [ ]

A. I called

B. I'm calling

C. I've called

D. I will call

看图，完成下列对话。

Zhen Zhuo: I want     l     join      2           3    club.

Mr Black: Can you      4          5   _ drum?

Zhen Zhuo: No,       6            7    . Mr Black:      8           9    play       10   _ true.

Zhen Zhuo:      11  _,     12     can't.

Mr Black: Can you play the guitar?                                  

Zhen Zhuo: Sorry, I can't play      13           14     , either.

Mr Black: .   15           16           17      do?

Zhen Zhuo: I can play     18           19    very well.

Mr Black: OK.Let me see.Mm...That's good.You can join the music club.

Zhen Zhuo:  Thank you very much.        

当颅内压持续超过（）时，称为颅内高压。

A.180mmHg

B.190mmHg

C.200mmHg

D.210mmHg

E.220mmHg