has become a problem 与 has became a problem 的区别~

A generation gap has become a serious problem as a result ,airpollution has become a serious problem has become a problem 与 has became a problem 的区别~ today pollution has become a seriously problem on earth. It has become a serious problem百度翻译中文 Nowadays(overpopulation)has become a problem we have to face 中become是不是应该用became A generation gap has become a serious problem关于这的英语完形填空 英语翻译Zhou Xueying's love of watching TV has become a big problem on her study he has become a A generous gap has become a serious problem.I read a r_______ about it in the newspaper,首字母填空 A lack of resources has become a big problem for this country.以A lack of resources has become a big problem for this country.为题写一篇120词左右的作文. 用A lack of resources has become a big problem for this countrystress写篇英语作文,150字左右! the population problem has become more serious in developing countries. 英语翻译Mobile phone has become a problem for middle schools.Some middle schools in Australia have banned(禁止) students from carrying mobile phones during school hours.Mobile phone use among children has become a problem for the school this ye Mobile phone has become a problem for middle schools.Some middle schools in Australia have banned students from carrying mobile phones during school hours.Mobile phone use among children has become a problem for the school this year.Several children 英语阅读理解.Mobile phone has become a problem for middle schools.Some middle schools in Australiahave banned(禁止) students from carrying mobile phones during school hours.Mobile phone use among children has become a problem for the schools When loneliness has become a 英语翻译想说是否细颗粒问题已经成为了一个很大的环境问题＂,写成＂Has particulate matter pollution become a serious environmental problem?对吗