Cloze.

     Parents are busy people. If they are working, they are usually not at home 1______ their children return

from school. Sometimes it is necessary for a parent to write 2______ after-school note for their children.

They sometimes put the note on the kitchen table, the refrigerator, 3______ another place where their children

are sure to find it. A note is often a 4______ way to "talk" with a child than using the telephone. For one thing,

parents have time to think about 5______ they want to say before they write. For 6______ another, the note

lists all the information in one place. It is easy to read again and again. People often forget all the details that 

7______ hear in a telephone call. Finally, cell phones can be turned 8______ or telephone calls not answered.

For these reasons, after-school notes are very popular with parents.

可按照如下4种操作来区分控制流程的各种改变情况，即条件分支、（）、（）和过程返回。