Mr.and Mrs .Long are a very forgrtful couple.For example,Mr

Mr.and Mrs .Long are a very forgrtful couple.For example,Mr Long sometiems goes to his office for work on Sunday morning.For he thinks it is Monday.And Mrs.Long sometimes forgets to cook supper for the family.
One summer they planned to fly to New York fo their holidays.They got to the airport only ten minutes before the plane left.So time was short,but suddenly Mrs.Long said she must tell Linda,their daughter,not to forget to lock the front door when she went to school.As Linda was then at school,they couldn't tell her about it by telephone.So the couple hurried to the post office.Mrs.Long wrote a short note to Linda while Mr.Long bought a stamp and an envelope.Soon the note was ready .They put the stamp on the envelope in a hurry and put it in the letter box.But suddenly Mrs.Long began to cry.The short note was still in her hand.She had put the plance ticket in the envelope!
1.The word "it" in the sentence"..and put it in the letter box.." really is ( )
2.Mrs.and Mrs.Long had to write a note to their daughter because they wanted to ask her( )
3.The topic sentence of the first paragraph is ( )
4.Write a title for the story:( )