用化学符号或化学式表示：（1）3个水分子______（2）5个氮原子______爱下问搜题

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问题填空题

用化学符号或化学式表示：

（1）3个水分子______（2）5个氮原子______（3）氢元素______（4）氧化镁______（5）地壳中含量最多的元素______

答案

（1）3H₂O

（2）5N

（3）H

（4）MgO

（5）O

单项选择题

* * 深部脓肿，诊断依据应是（）

A.皮肤红肿

B. * * 肿胀

C.发热

D.局部波动感

E.穿刺抽到脓液

补全对话，情景问答

根据对话内容，从方框内选择合适的句子补全对话。（有两项多余）

A. What else?
B. Never mind.
C. Yes, we do.
D. No, I haven’t.
E. No. T

he telephone was busy.
F. We are leaving in ten minutes.
G. Yeah. I have put the bag in the car

(F=Father; T=Tom）
F: Has everything been ready, Tom? (1)________
T: Yes, I think so.
F: Have you packed your bag?
T: (2)_________
F: Have you fed the dog?
T: Oh, no. I forgot. I’ll do it now.
F: Have you said goodbye to your teacher?
T: (3)_________
F: Have you brought a guidebook?
T: Do we need to?
F: (4)_________
T: Okay. I’ll take one.
F: (5)_________ Oh yeah, have you watered the plants yet?
T: Mom did it.
F: Now, we are ready. Let’s go!