焊接低碳钢，有色金属，低合金钢采用（）焰。 A.碳化焰 B.氧化焰 C.中性焰

用N_A表示阿伏加德罗常数的值，下列叙述正确的是

A．1molFeCl₃与沸水反应生成胶体后，含有N_A个Fe(OH)₃胶粒

B．标准状况下，1.12 L的HCHO所含的原子数是0.2N_A

C．1 L0.5mol/LNa₂CO₃溶液中含有的CO₃^2－数目为0.5N_A

D．16.9 g过氧化钡（BaO₂）固体中阴、阳离子总数为0.3N_A

组成机床的零件出现裂纹、电气设备设施绝缘质量下降等现象属于( )。

A．机床、设备内部缺陷

B．转速正常

C．输入输出参数异常

D．温升异常

阅读理解。

     Get a FREE YEAR! Order NOW and get a FREE YEAR of Parents? magazine! That's 2 full years

(24 issues) for the regular 1-year rate-just $12. But HURRY, this offer won't last! (U.S. orders only,

please.)            

     Every issue of PARENTS is filled with practical advice from leading doctors and child experts ...toys

and games that develop reader-tested products and more!

     100% Money-Back Guarantee: You must be pleased, or you may cancel any time during the life of

your subscription and get all your money back - no questions asked. Parents? Magazine is published 12

times per year. Savings are based on $12.00 annual subscription rate. State taxes may apply to your

order.    

     E-mail address required to access your account and member benefits online. We will not share your

e-mail address with anyone. Click here:  www.parents.com/privacy to view our privacy policy.  

1. The purpose of the passage is ______.

A. to introduce a new magazine    

B. to help parents with their daily life

C. to attract more subscribers      

D. to collect more money for charity

2. Which of the following is true according to the ad?

A. Only $12 is to be paid for 24 issues of the magazine

B. Readers can get a free offer of the magazine any time of the year

C. Readers from all over the world can enjoy the free offer

D. Readers can communicate face to face with child experts on the Internet

3. A reader subscribed PARENTS 3 months ago, but now he finds the magazine dissatisfying.

    What can he do?    

A. He can cancel without getting your money back.

B. He can cancel after answering a series of questions.

C. He can e-mail them to access your bank account to get all your money back.

D. He can cancel and get all money back without answering any questions.

地震荷载的大小与建筑物所在地区的( )地震烈度有关。

A．地震动土压力
B．地震惯性力
C．地震烈度
D．地震震级

新安装验收的桥式起重机主梁上拱度为0.8S/1000，则拱度为不合格。