American English has so many dfialects because people have come from all over the world.（people have
题目
American English has so many dfialects because people have come from all over the world.（people have come from 为什么要用have这个现在完成时态 能说 because people come from all over the world)
答案
这个问题还真不太清楚.
从语法上讲,改为一般现在时是没有错误的；也许是习惯问题
举一反三
已知函数f（x）=x，g（x）=alnx，a∈R．若曲线y=f（x）与曲线y=g（x）相交，且在交点处有相同的切线，求a的值和该切线方程．
我想写一篇关于奥巴马的演讲的文章,写哪一篇好呢?为什么好
最新试题
热门考点