判断对错．

分数的分子不同，也就是分数单位不同．

硝酸钾在不同温度时的溶解度如下表所示，根据表中给出的数据回答下列问题：

如图，AB∥CD，以点A为圆心，小于AC长为半径作圆弧，分别交AB，AC于E，F两点，再分别以E，F为圆心，大于 EF长为半径作圆弧，两条圆弧交于

点P，作射线AP，交CD于点M．若∠ACD=114°，则∠MAB的度数为____°.

方框中所给单词的适当形式填空，使对话通顺、正确。每词仅用一次（每空一词）。

Sandy: Mom, I'm really worried.

Mom: Why? What's the ____?

Sandy: I can't find my schoolbag.

Mom: Well, where did you last put it?

Sandy: I can't remember! I ____ a concert yesterday so it might still be in the museum hall.

Mom: Do you have anything ____ in your schoolbag?

Sandy: No, just my books, my pink hair band and some tennis balls.

Mom: So it can't be ____.

Sandy: Oh, wait! I went to a picnic after the concert. I remember I had my schoolbag with me at the picnic.

Mom: So could it still be at the park?

Sandy: Yes. I left early, before the rest of my ____. I'll call them now to check if anybody has it.

下列有关“安全操作”的叙述中正确的是（    ）