在一定条件下,可发生反应:RO3n- +F2 +2OH-==RO4-+2F-+H2O。则RO3n-中R元素的化合价是 [ ]
A.+4
B.+5
C.+6
D.+7
答案:B
A: Have you seen Li Ling these days?
B: No, she’s gone to Jilin 1. __________ her grandfather.
A: Has she ever been there before?
B: Yes, she lived there before she came here.
A: Have you 2. __________ her?
B: Yes, I’ve just received a letter from her.
A: 3. __________?
B: She said she had a very good time and would 4. __________ there for another week.
A: What else did she say?
B: She also wanted me to give her best 5. __________ to you.
A: It was very nice of her to say so.
简述解放区在1945到1946开展减租减息运动的意义?