【题目】Tom is a friend of ______, and he often helps ______ with her Math.（ ）
A. Lily; herB. Lily's; she
C. Lily; sheD. Lily's; her
【答案】D
【解析】
考查名词所有格和人称代词。由题，"a friend of sb's"为固定搭配，意为"某人的朋友"，为双重名词所有格；"help sb with sth"意为帮助某人某事，其中sb为宾语，Lily's为所有格形式，she为主格，her为宾格。 故选：D。