many ways， for us，are， to keep in touch， there（连词成句）．
You'd better not stay out with your friends． You need to come back by 9p．m．
I've heard many beautiful clothes are on in the clothes store． let's go shopping now．
在空白处填入一个适当的词，使句子意思完整、语法正确．
You're supposed to at the door and wait before entering the office．
One day， you will leave your parents． You have to learn to look after ．