1. I exchanged them multiple times, could not figure out
2. yes, that sound better. I try to use "which" to refer the first two scentences, but can not make it work :(
3. good catch, I can not distinguish these two. I will check on dict.cn.
4. I realized that when I heard the original one.
5. thanks. I can not make the spelling check in my word work :(
Thanks again.
