问题补充：
Li Rong told me what difficulties she had had English before she came to Canada.
A. learning
B. learn
C. learnt
D. to learn
答案：
(答案→)A. learning
B. learn
C. learnt
D. to learn
解析：考察非谓语动词..句意:李荣告诉我,在她来加拿大之前学英语是有多么困难. what difficulties she had had是后置定语,现在分词作宾语补足语表示正在进行的伴随性动作,和句子主语是主谓关系.故选A.
