It is not enough onlythe rules of grammar if you want to learn English well.A. keeping in

问题补充：

It is not enough onlythe rules of grammar if you want to learn English well.

A. keeping in the mind

B. to keep in mind

C. to keep in your mind

D. keeping in your mind

答案：

@@A. keeping in the mind@@(答案→)B. to keep in mind @@C. to keep in your mind @@D. keeping in your mind

解析：keep sth. in mind 为固定短语，意为“记住，记在心里。”only to keep sth. In mind为动词不定式作主语。