请问谁会这个题？告诉我为什么1.—I hope you don't mind my opening the window

请问谁会这个题？告诉我为什么
1.—I hope you don't mind my opening the window.
---_____.It's much too hot in the room.
a. Of course not b.Never mind c.All right
答案是 a . 请告诉我b c 的用法
2.Have you ever been to Suzhou, Mary?
Yes, I____ there for three days with my friends last month.
a. went b. was
答案是a .为什么b I was there (我在那待了3天）这个为什么不对？