英语对一个包裹提问用what is还是what are?

问题描述:

英语对一个包裹提问用what is还是what are?
what is in it?
what are in it?
what is in it?和 what is this in it?有区别吗
what are in it?和 what are they in it?有区别吗

用What's in it
对于知道里边为可数物品时,可以用what are in it
what is in it指没有看到里边东西情况下的提问,what is this in it指看到了里边的东西即“this”,并对this 进行提问,
下句同