设向量a=(1，0)，b=(sinθ，cosθ)，0≤θ≤π，则|a+b|的最大

用词的适当形式填空。

1. Do you learn English by _______ (ask) friends for help?

2. He enjoys _______ (help) others in trouble.

3. Miss Liu said that _______ (read) was good for us.

4. What is the best way _______ (study) physics?

5. He has trouble _______ (work) out the math problems.

6. What about _______ (go) out for a walk?

7. It is _______ (important) for me to know his story, because I don't know him.

8. Thousands of people _______ (lose) their lives in the earthquake last year.

9. Can you tell me the _______ (different) between the two words?

10. We are _______ (take) notes while the teacher is giving a lesson.

铝和氧的亲和力很大，极易在铝件表面形成（）氧化膜，隔离空气、水、硝酸等介质的腐蚀。

六种通用水泥的名称和代号是什么？

（）不可能造成自动磨边机加工的镜框边显示不平滑。

A、扫描器探头没有置入镜架槽内

B、样板边缘上有不规则毛刺

C、被扫描镜架未装正

D、镜框接头处有错位或缝隙，镜架鼻托阻挡扫描针