冬天大规模袭击我国的寒潮大都来自西伯利亚。西伯利亚成为寒潮生成地的最不可能的原因是(

C70、C70H型通用敞车分别装用何种型号的转向架？

水湿困脾型鼓胀的主症是（）。

A.腹大胀满，脉络怒张

B.腹大胀满，如囊裹水

C.腹大胀满，早宽暮急

D.腹大胀满，脘腹撑急

E.脘腹坚满，痛如针刺

某溶液中可能含有Na⁺、NH⁺₄、Ba²⁺、SO^2-₄、I^-、S^2-．分别取样：①加氯水和淀粉无明显现象；②用pH计测试，溶液显弱酸性．为确定该溶液的组成，还需检验的离子（　　）

A．Na⁺

B．SO^2-₄

C．Ba²⁺

D．NH⁺₄

阅读理解。

     You've attended all the classes,done all of your homework and you think you have grasped

the material.But then the day of the test comes.Suddenly,you feel so nervous that you can't answer

those questions you knew the answers to just last night.If this sounds like you,you may have a

case of test anxiety (焦虑)．

     Test anxiety can be a real problem.When someone is stressed out over a test,he or she

may not be able to do his or her best work.Feeling ready to meet the challenge,though,can keep

test anxiety at a proper level.

     Use a little stress to your advantage.Stress is your body's warning mechanism (装置)-it's

a signal that helps you prepare for something important that's about to happen.Instead of worrying

too much about the test,take  an active way.Let stress remind you to study well before a test.Then

you'll stop your stress from being out of control.

     Ask for help.Although a little test anxiety can be a good  thing,too much of it is another story

entirely.If sitting for  a test makes your mind go blank and causes you to miss answers that you know,

then your level of test anxiety  probably needs some attention.Your teacher,your parents,or a tutor

can be a useful resource to talk to if you always get too much test anxiety.

     Be prepared.Many students find that their  test anxiety is  reduced when they start to study better.

It works-the better you know the material,the more confidence you'll have.

1.What is this passage mainly about?

A．What should be done before a test.

B．How to deal with test anxiety.

C．What causes test anxiety.

D．What test anxiety is.

2．The underlined word "grasped" in Paragraph 1 probably means________.

A．received    

B．passed

C．understood  

D．finished

3．From Paragraphs 2 and 3 we can learn that________.

A．it's hard to keep test anxiety at a proper level

B．test anxiety cannot be avoided

C．only lazy students have test anxiety

D．a little test anxiety might be helpful

4．In Paragraph 4,the writer suggests a student who feels too nervous before a test should________.

A．find a quiet place to relax for a while

B．talk to someone to get over the anxiety

C．have a good time with some friends  

D．find out if others feel the same

5．What can we infer from the passage?

A．Test anxiety is a kind of serious illness.

B．Getting prepared can reduce test anxiety.

C．Only teachers can help students get over test anxiety.

D．The more tests a student has,the less anxiety he/she will have.

在容器不变的密闭容器中，在一定条件下发生反应：2A（g）＝B（g）+C（S），且达到化学平衡，当升高温度时其容器内气体的密度增大，则下列判断正确的是（）

A.若正反应是吸热反应，则A为非气态

B.若正反应是放热反应，则A为气态

C.若在平衡体系中加入少量C该平衡向逆反应方向移动

D.压强对该平衡的移动无影响