为什么是by weight而不是bu the weight?

为什么是by weight而不是bu the weight? You can't imagine that rats eat 40 to 50 times their weight.为什么是 their weight 为什么是by the light of the room而不是on 为什么是He doesn't like 而不是 He likesn't 请问为什么是didn't imagine,而不是haven't imagine? 为什么是why not go by coach而不是why not going by coach Amy is sure__(come)here by plane 为什么是to come 而不是cAmy is sure__(come)here by plane为什么是to come 而不是come I have to be home by 10：00pm为什么是be home而不是go home There are some flowers ____ the pictureA.atB.inC.onD.by为什么是C而不是B? A man is known by the company he keeps为什么是he keeps而不是his keeps I ask them to read it______________.为什么是read it themselves而不是read it by themselves? 怎样变这个主动句为被动语态?They don't use the room(他们未使用该房间）,变为被动语态,我觉得应是The room does't used by them,而答案是The room isn't used by them 为什么是isn't 而不是doesn't啊, 900ppm by weight 为什么是The door doesn‘t lock.而不是The door doesn’t be locked 为什么是My cousin doesn't like bananas.而不是My cousin don't like bananas. 英语-为什么是he didn't get up yesterday而不是he wasn't get up yesterday she don't know my name NELLY的歌 为什么是don't 而不是doesnt 为什么是it isn't good for you而不是it doesn't good for you