题干
Millie and Kitty are good friends, they often _________ each other _________study.
A：helping; with
B：help; to
C：helping; to
D：help; with
答案(点此获取答案解析）
D
Millie and Kitty are good friends, they often _________ each other _________study.
A：helping; with
B：help; to
C：helping; to
D：help; with
