根据对话语境，在空白处填写恰当的句子补全对话
A: Good morning!
B: Good morning! I’d like to join the school volunteer project, but____ .
A: OK, don’t worry. Let me help you.____ ?
B: I love singing and telling stories.
A: Well, you could help look after young children on weekends.
B: ____ . I can sing for them and tell them stories. I’m sure that  children will love me.
A: I agree with you. ____ ?
B: Sure. I am Peter White. My telephone number is 885-276.
A: OK. I’ll call you as soon as possible.
B: ____ .
A: It’s my pleasure.

测定土壤中细菌数量一般选用10⁴、10⁵和10⁶倍的稀释液进行平板培养，而测定真菌的数量一般选用10²、10³和10⁴倍稀释，其原因是（　　）

下图为我国主要山脉和河流分布示意图，读图，完成下列各题。

为了防止火灾的发生，在宾馆房间的天花板上大多装有一个传感器，该传感器是（  ）