802.11b和802.11g的工作频段在2.4GHz(2.410GHz-2.483

题型:填空题

问题:

802.11b和802.11g的工作频段在2.4GHz(2.410GHz-2.483GHz),其可用带宽为83.5MHz,划分为()个信道,每个信道带宽为()。

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题型:填空题

阅读理解。

     Do you get enough sleep? With so much homework it's often difficult to get the rest you need. But you

need to try, because sleep keeps you healthy and it stops you getting fat. Recently, a group of U. S. scientists

did a study (研究) of kids aged between 8 and 13. The study found that if kids sleep for just one extra

(额外的) hour each day, the chance of their getting fat is cut by about 30 percent.

     Why? When people don't get enough sleep, they become tired. When they are tired, they don't exercise

enough. Also, kids like snacks. If they are awake (醒着的) an extra hour or two each day, they have more

time to eat snacks or other unhealthy foods.

     So, how much sleep should you get? Scientists suggest 10 to 11 hours a night for kids aged 5 to 12. For

older kids, eight to nine hours will do.

1. How many reasons are given why people might get fat without enough sleep?

A. 3.

B. 2.

C. l.

D. None.

2. If you are under 10, how long do the scientists advise you to sleep?

A. 10 to 11 hours.

B. 8 to 9 hours.

C. 8 to 13 hours.

D. As long as possible.

3. Where was the study done by the scientists?

A. In China.

B. In Britain.

C. In America.

D. In Japan.

4. What does "eight to nine hours will do" mean? 

A. Eight to nine hours' sleep will be good and enough.

B. Eight to nine hours' sleep will be too long.

C. Eight to nine hours' sleep will help get fat.

D. Eight to nine hours' sleep will help eat snacks and unhealthy foods.

5. What does the passage talk about?

A. How to get long sleep.

B. How to keep fat.

C. Enough sleep makes people healthy and slim (苗条).

D. Long sleep makes people healthy and slim.

题型:填空题

要判断电流产生的磁场方向,需要用什么定则?

题型:填空题

鸡蛋孵化时一般在()胚龄进行头照。

A、2-3

B、5-7

C、8-10

D、11-12

题型:填空题

民事法律关系的客体是民事权利和民事义务共同指向的对象。在货物买卖合同关系中,民事关系客体是( )。

A.货物
B.货物的价格
C.买卖合同
D.交付标的物和货款的行为

题型:填空题

关于输卵管妊娠的治疗,下列哪项错误()

A.治疗原则以手术治疗为主,其次是非手术治疗

B.间质部手术,手术应做子宫角部及患侧输卵管切除,必要时切除子宫

C.有生育要求的,可行保守性手术

D.有休克者待休克控制后再手术

E.输卵管间质部妊娠禁止采用中医治疗

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