-Mary,the door bell is ringing.Who's that?-Oh,it's my friends's sister,Tina.请解释下、为什么后面的答句那个代词要用it 而不是用she's呢?请充分的解释、要能说服别人的.

While we are watching TV,the door bell rings.能不能把后半句改成the door bell is ringing. .Just after putting away the dishes _______..the door bell rang B.Nancy heard the door bell ringC.the door bell was rung D.someone knocked at the door ___at the door ,i'v hardly rung the bell ____ the door opened.为什么用standing ,before? the door bell rang just now这个可以用过去完成时吗 the door bell had rang just now .再如 i had broken a cup just now the bell As soon as the bell rang for break,the door opened and in came Mr Black. While mother (put)Cathy to the bed ,the door bell ( )(ring)适当形式填空 When the bell rings ,there was w（开头的什么单词） rush for the door. we had no sooner sat down to supper than the door bell rang.倒装怎么写? Mary asked him to close the door.改为直接引语 what's the matter with your leg?Mary Next Door Mary is closing the door.改为否定句 the children -------cards when the door bell rang .a.played c.plays d.played d.were playing 3 While watching television,____.Athe doorbell was rung Bthe bell of the door rang Cwe heard the doorbell ring to her horror,it was no longer there.she ran to the next door and rang the bell so loudly, -Mary,the door bell is ringing.Who's that?-Oh,it's my friends's sister,Tina.请解释下、为什么后面的答句那个代词要用it 而不是用she's呢?请充分的解释、要能说服别人的. There is a wind-bell on the door.划线提问,在on the door Kitty flies her kites very high.fli.划线提问,在flies her kites 27 If nobody answers the door bell ,try ___ the back door.A to knock at b.to knock c.knocking at d.knocking 需要详细分析