2016年我国决定全面实施一对夫妇可生育两个孩子政策，这意味着长达30多年的独生子女政策正式结束。读我国15～64岁年龄段人口变化图，读图，完成下列各题。

C）根据对话内容，从下面方框中选择适当的单词或短语填空，使对话内容完整正确。

Tom： I give up! I____ can't learn English!
Amy:  Why do you say that? I think you are making a lot of____ .
Tom:  No, I'm not. I try and try and I still can't speak it very well.
Amy:  Learning any language ____  a lot of effort. Please don't give up.
Tom:  Amy, I know you always____ English. Can you offer me some valuable advice?
Amy:  Listening to English tapes and watching English movies may be helpful. But always remember your English will improve if you are really____ it.
Tom:  Good idea. I will try to love English.

若3a^m+2b⁴与﹣a⁵b^n﹣1的和仍是一个单项式，则m+n=____．