下列做法中，符合安全用电要求的是_刷题宝

题干

下列做法中，符合安全用电要求的是（　　）

A：熔断器安装在零线更安全

B：更换灯泡时，先断开开关

C：发生点火灾时，要立即给着火的物体泼冷水

D：发现落在地上的高压线，要靠近检查是否带电

上一题下一题 0.0难度选择题更新时间:2017-10-01 12:14:37

答案(点此获取答案解析）

B

同类题1

补全对话。

A：Hi, Tom. ____

B：Yes, very much. Last week, I went to Mount Tai with some friends.

A：Really? ____

B：It was great．We had a good time there．

A：____

B：Yes, it is．It's one of the most popular places there.

A：____

B：It's about 1,500 metres high. It took us five hours to get to the top．

A：I see. ____

B：Of course. We got up earlier. It was a wonderful experience for me．

A．Did you see the sunrise there?

B．How did you like it?

C．Where did you get to the top?

D．How high is it?

E．Do you like mountain climbing?

F．What's the highest mountain in the world?

G．Mount Tai is in Shandong Province, isn't it?

同类题2

同类题3

下列方程中，解是x=4的方程是（）

同类题4

下列各组热化学方程式中，△H₁>△H₂的是
①C(s)＋O₂(g)===CO₂(g)     △H₁      C(s)＋1/2O₂(g)="==CO(g)     " △H₂
②S(s)＋O₂(g)===SO₂(g)     △H₁      S(g)＋O₂(g)===SO₂(g)        △H₂
③H₂(g)＋1/2O₂(g)===H₂O(l) △H₁     2H₂(g)＋O₂(g)===2H₂O(l)     △H₂
④CaCO₃(s)===CaO(s)＋CO₂(g) △H₁     CaO(s)＋H₂O(l)===Ca(OH)₂(s) △H₂

同类题5

读黄河“地上河”示意图，完成以下问题。

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