1:做这道题你应该看后面的复数-works,所以它的动词应该选are,而不是is.如果它说的是一个数字概念,那应该选is
2:A I don’t know who’s the book is written by?
(who's应该改为who)
B:Can you tell me whose the book is written by?
(whose改为who)
D Nobody knows whose is the book written by?
(Nobody knows who the book is written by?
whose和who一个是谁的 一个是谁,一个做宾语,一个不做,其次宾语从句用陈述语序
3：It doesn't metter 没关系的意思 回答道歉等用的
That"ok