题干
—She is ______ and has trouble walking,so we help her go to school every day.
—You're a good boy,son!It's good to help those ______.
—You're a good boy,son!It's good to help those ______.
A：disabled; in need
B：ill; in fact
C：lonely; in a way
答案(点此获取答案解析）
A
表示把集合M中的元素x映射到集合N中仍为x，则a+b为 （ ）
