One of the difficulties we have English is how to remember new words and expressions.
A. to learn
B. in learning
C. learn
D. learned
网友回答
A. to learn
(答案→)B. in learning
C. learn
D. learned
解析：句意：我们在学习英语中的困难之一是如何记住新单词和表达方式。Have difficulty in doing sth做某事有困难。结合语境可知选B。