题目内容
在空格上填上一个适当的词，使句意完整。
Who is the letter ________ the desk ________?
on from/to
Is your sister ________ your brother in China now?
Does your father go to work ________ bus or ________ foot?
Uncle Sam works ________ a farm, not ________ a factory．
“It’s time ________ us ________ here．”“Yes, Let’s go．”
