为什么"This is a photograph I took during my trip to Australia."里面可以不需要"of"单词?

This is a red jacket为什么错误? Is this a your rule为什么不对 What is this 是This is a pen.还是.It is a pen?为什么? 为什么This is paper中间不用加a,也就是为什么不说This is a paper This is a bag.( )bag is yelloy.填什么为什么? hello!_______?this is tom.a.who is this b.who is that 为什么? What is this in english?A This is a bag B It is bag C It is a bag 为什么 This is a flower .为什么要加a this is kangkang.为什么用this is Is this a car?回答为什么不能是Yes,this is. this is good exercise 为什么不是this is a good exercise ? Mom,_____ my English teacher A：this is B:she is为什么用this is而不用she is This is a picture of my room 为什么填of 为什么说This is my a pen是错的? 为什么不能说 This is my a pen Is this a book? Yes,this is. This is a man提问( ) is this? What's this?This is _____N.A.a B.an C./ 选择哪一个?为什么?