T he book was writeen in 1978,(since when)the education ststem has witnessed great changes括号里为什么不换成during which ,which不是要引导非限制性定语从句么since when 的含义是什么啊,可以给个详细的解释么

was he naughty yes he was /no he wasn't . With his attention ____ on the book he was reading,he didn't notice what had happened.A.focuses B.focused C.to focus D.focusingWhich one?why? 结果状语从句!He was abosrbed in the book so much that he didn;t hear the voice.有错误么?这样虽然不地道，但是对吗、 He was heard() out (go)When I was reading a book.he was heard () out.(go) 是He doesn't return the book back.还是He doesn't return back the book. 用--ing分词改写句子He cut off the electricty quickly so that an accident was prevented.The old man was fast asleep and held a book in his hand.As he was crossing the road, he was run over by a car.As he didn't know English, he couldn't underst He was walking ____ ____ street with a book. With his attention ___ on the book he was reading ,he didn't notice what had happened.With his attention __ on the book he was reading ,he didn't notice what had happened.A.focuses B.focused C.to focus D.focusing 为什么?请详细说明每个选项 ___ in a book,he didn't even notice a car was coming towards him.A to lose B lost C losing D haviD having lost A book was written on the subject.He has written a book on this subject.时态? 帮忙翻译这篇英语作文!If you came from a poor family and couldn't go to a good school,could one book change your life?It did for Srinivasa Ramanujan,a bright young Indian boy.When he was 15 years old,he found a book about maths.It was a book Jim ____ (read) that book,didn't he? He doesn't think this book is interesting.有错吗? Mike ____(read) this book ,hasn't he ? he was now returning home with the money which he had put in his pocket book. 21.It was not until he arrived in class _____ realized he had forgotten his book. He's read this book before ,< A hasn't he B doesn't he C isn't he D wasn't he老师复印的卷 The book was so expensive that he couldn't buy it句型转 It's such an important match.We can't missI'll send my mother a flower on her biethday(句型转换)