常用的数字信号编码有()。A、非归零码B、曼彻斯特编码C、差分曼彻斯特码D、PCM码

题型:多项选择题

问题:

常用的数字信号编码有()。

A、非归零码

B、曼彻斯特编码

C、差分曼彻斯特码

D、PCM码

考点:网络设备调试员网络设备调试员题库
题型:多项选择题

平衡是指()

A.正中时有广泛均匀的接触

B.前伸时、前后牙均有接触

C.侧方颌时、工作侧和非工作侧均有接触

D.B与C

E.A与B与C

题型:多项选择题

阅读理解。

     I have seven bags. Three bags are big, and the other four bags are small.I have some basketballs

and volleyballs. I put two volleyballs in each (每一个) small bag. And I put two basketballs and two

volleyballs in each big bag.The number of the volleyballs is my age (年龄).

1.I have ______ volleyballs.

A. three

B. five

C. fourteen

D. seven

2. I have ______ basketballs.

A. six

B. eight

C. ten

D. twelve

3. What's in those big bags?

A. Two basketballs and six volleyballs.

B. Eight basketballs and six volleyballs.

C. Six basketballs and six volleyballs.

D. Eight basketballs and eight volleyballs.

4.Where are the basketballs?

A. In the big bags.

B. In the small bags.

C. In a big bag.

D. In a small bag.

5. How old am I?

A. I am six.

B. I'm twelve.

C. I'm fourteen.

D. I am sixteen.

题型:多项选择题

我国化学试剂分哪几个等级?其标志是什么?

题型:多项选择题

支气管平滑肌上的肾上腺素受体是

A.β1受体
B.β2受体
C.M受体
D.N1受体
E.N2受体

题型:多项选择题

总体来看()发展将成为新一轮能源技术革命的重要推动力量。

A.新能源

B.绿色能源

C.特高压技术

D.智能电网

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