如图所示的家用电器中，利用电流的热效应来工作的是（　　）

NaBr+H₂SO₄→HBr+NaHSO₄

CH₃CH₂OH+HBr $\stackrel{△}{\to }$  CH₃CH₂Br+H₂O

化学兴趣小组根据实验原理设计如图的装置．

根据题意完成下列填空：有关数据列表如下：

根据下面对话情景，在每个空白处填上一个适当的单词，使对话的意思连贯、完整。

A: Hi, excuse me.

B: Yes. How can I ____  you?

A: I'm new in town. Where is the Science Museum, please?

B: Go along Center Street and ____ right on Main Street. Then you'll see it on your left. It's across from the park.

A: Is it far from here?

B:____ , it's quite far from here. And you can take a bus.

A: Which ____  can I take?

B: The No. 5 bus.

A: Is____ a bus stop near here?

B: Yes, there is. I can walk with you.

A: Oh, that's great! Thanks so much.

B: No problem.

关于旅游业经济职能的正确叙述是（  ）