Are these question easy to answer?yes.-- of them is a piece

Are these question easy to answer?yes.__ of them is a piece of cake for you.A.All B.Any C.None
但我添的是A 不可以把All of them看成一个整体吗?也符合后面的意思.

这类问题不管用上面哪一个选择都可以有正确的表述方法,意思都一样.
哪个字开头配哪一种说法就有讲究了,你无需死记但必须彻底理解.
Any of them 在这里是唯一选择,因为 is a piece of cake,它们其中任何一题 ...
换个词看看
《例》
Yes.All of them should be easy for you.
Yes.None of them should give you any problem.
回答的意思其实都一样：这些问题都很简单.
选择用 All 作为句首,后面就绝对不会考虑 a piece of cake 这种俚语.