某人因食用了带浓缩甲型肝炎病毒的毛蚶而感染了甲型肝炎，那么认为毛蚶是A．传染源 B．

下面是一位同学在学校论坛上发的帖子。假设你是Mary， 请根据他的这三个问题给出你的建议。开头已给出，字数：70词左右 。

Dear friend, 

What a terrible day today ! This morning I was late for school again and my teacher was very angry with me. Then I found I left my math book at home. Because I played computer games too late last night, I fell asleep in class this afternoon. I didn’t hear what the teacher said. I didn’t know how to do my homework. I really don’t know what to do. Could you please give me some advice?

Yours,

Looking for help

参考词汇：make mistakes, say sorry to... ;  get...ready ;   listen carefully in class；                     spend more time on...；help...with..

Dear looking for help ,

Here is some advice for you .

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Yours,                      

Mary 

錾削铜、铝等软材料时，楔角取()。

A、30°～50° 

B、50°～60° 

C、60°～70° 

D、70°～90°

其他已配剂量含激素或品目2937产

我国的人民币票面上印有蒙古族、维吾尔族、藏族、壮族四个少数民族的文字。这表明

A．我国只有四个少数民族有自己的文字

B．我国各民族都有使用和发展自己的语言文字的平等权

C．民族间的语言差异将长期存在

D．少数民族享有自治权

术中输血最主要的目的是（）。

A.改善氧的运输能力

B.改善微循环

C.补充血液胶体成分

D.补充凝血因子

E.提高机体的免疫力