It was strange that she should have gone away without saying good-bye.求解释为什么要用should have gone?

it is strange that 英文句子改错：but it was strange that we could not open the door I thought that was pretty strange at first,but now im used to it ——that I went in to see what was happening.A so strange did it feelB so strange it feltC so strangly did it feelD so strangely it felt这个strange到底修饰什么.为什么不是副词. It was very strange(感） It was very strange(感）感叹句 You can imagine how strange it was! you kan imagine how strange it was! you can i____how strange it was she thought it was strange否定句 she __ __ it __ strange求火速 How strange it was to see an alien in the street!a.what strange b.what a strange c.how strange things d.how strange 为什么选d .（虚拟语气）Was it strange that she _____ when she got that good new?A should cry B has criedC would cry D might have cried 同义句转换The baby looked very strange when it was bornThe baby looked very strange ------- -------. 连词成句 how,it,you,imagine,was,can,strange People said that there was gold in that cave转换句型看例题:People say that there is a strange creature in the Himalayas.It is said that there is a strange creature in the Himalayas.There is said to be a strange creature in the Himalayas.下面 It is strange that she________(give up) her plan. but all what she can say was that it seemed strange to her that i hadn't talked of anything about…but all what she can say was that it seemed strange to her that i hadn't talked of anything about the pen the day she talked to me.after the text.A. r It was strange that she should have gone away without saying good-bye.求解释为什么要用should have gone?