Some students have trouble grammar while others have difficulty new words．
A. in；remember
B. for；to remember
C. on；remembering
D. with；remembering
网友回答
A. in；remember
B. for；to remember
C. on；remembering
(答案→)D. with；remembering
解析：考查句型have trouble with sth和have difficulty in doing sth 并且in可以被省略。意为：做某事有困难。句意：一些学生学习语法有问题，而另一些学生记单词有困难。根据句意选D。