这个英语句子为什么用was啊,怎么不用is.he was laughing away to himself all the time.

这个英语句子为什么用was啊,怎么不用is.he was laughing away to himself all the time. she said i was hard-working 这个句子中为什么用I而不用me The letter that I received was from my father 这个句子中为什么用that不用which I WISH I WERE A BIRD.怎么这句子里面用WERE,不用WAS啊?是不是书上写错了为什么用WERE啊. I dont know why he was late.这个句子里为什么用why不用that?我打错了　是Idont know the reason why he was late 为什么用whom 而不用who在句子I am sorry whom your handbag was stolen中,为什么不用who Shanghai is the city where I was born,为什么用where,不用which,where不是做状语吗?在这个句子里,where修饰,Shanghai Shanghai It was in the supermarket that i bought the computer.为什么用that而不用其它的呢?而且这个句子是定语从句吗,同志们,急用 英语中带must的句子变反义疑问句怎么变?I must go now ,must't I.这里为什么用 must't I.不用need't I 关于英语中语法的问题Was it because Jack came late for school _______ Mr.Smith got angry.为什么这个句子用他that,而不用why i know you batter than she这个句子为什么用she不用her It was a matter of＿ would take the position.为什么用who不用Whoever?请分析这个句子 It gave me quite a shock to be told I was seriously ill.为什么to be told前面为什么不加i was怎么理解这个句子结构 It was in 2000 when he was in middle school 这个句子为什么不用强调句It was.that结构? 一个简单句子中的英语语法I was unaware of the danger为什么不用I was unawaring the danger? 为什么英语有些句子要用is、are、was,有些就不用呢.例如she is a beautiful girl! I was having a hard time finding the school.这个句子为什么用having I could play football very well when l was younger改成用he作主语.这个句子该怎么变?为什么?