题干
— Tommy, do you know if Frank ______ to the zoo this Sunday if it _______?
— Sorry, I have no idea.
A：will go; is fine
B：goes; is fine
C：will go; is going to be fine
D：goes; will be fine
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 （ ）