题干

---Mary can’t help her mother______the house. Why ?
--- Because she is busy____ a cake.
A.cleaning; to makeB.cleaning; making
C.to clean; makingD.to clean; to make
上一题 下一题 0.4难度 单选题 更新时间:2018-03-10 09:06:48

答案(点此获取答案解析)