热力设备检修需要电气运行值班人员做断开电源安全措施时，若热机检修工作负责人不具备到配

I          send emails now.[ ]

A. can        

B. do        

C. does        

D. need

根据对话情景，在空白处填入合适的句子。

(Jill is not feeling well, so her mother takes her to the hospital.)

Jill: Good morning, doctor.

Doctor: Good morning. 1.__________________?

Jill: This morning I had a pain in my head.

Doctor:  2.__________________?

Jill: I'm feeling even worse.

Doctor: Open your mouth and say "Ah".

Jill: Ah...

Doctor: You have a cold. Let me take your temperature. 3.__________________.

Jill: Is it serious?

Doctor: No, it isn't. 4.___________________.

Jill: Really? But I don't feel any better now.

Doctor: Well, take this medicine three times a day. 5.__________________.

Jill: OK. Thank you.

新疆有“早穿皮袄午穿纱，怀抱火炉吃西瓜”之称，意思是该地区昼夜温差变化很大．在这种情况下，司机总是愿意在深夜加油，为什么？怎样解决这个问题？

建筑基坑采用水泥土桩复合土钉墙支护时，水泥土桩伸入基坑底的长度宜大于桩径的（）倍，且不应小于1m。（）

A.2

B.3

C.4

D.5

将0.1mol·L^-1的HAc与0.1mol·L^-1的NaAc混合，混合溶液中加水稀释至原来体积的2倍，其H⁺浓度和pH值变化为( )。

A．原来的1/2倍和增大
B．原来的1/2倍和减小
C．减小和增大
D．不变和不变