中华人民共和国的成立和社会主义制度的建立，是20世纪以来中国社会经历的第二次历史巨变。与这两件大事相关的年代分别是（    ）

情景交际

        A. that's too bad. 

        B I left my cell phone in one of the clothing shops.

        C It doesn't matter.  

        D You should go to the police station.

        E It wasn't there .

        F That's really kind of you. 

M: Why do you look so unhappy , Jane ?

W: I went shopping this morning .____

M: Oh,____ Did you get back ?

W: No, I didn't . I went back to the clothing shop and the shop assistant said that ____. I think someone must have taken it  

M: I think____         

W: I think so, too

M: Well, I can go there with you

W:____ Thanks a lot

M: Not at all . Let's go now

W: OK

打扫房间时，小明用干绸布擦穿衣镜，发现擦过的镜面黏上细小绒毛。这是因为擦过的镜面因____而带了电。带电体有____的性质，所以绒毛被吸在镜面上。