Billy is a nice boy . he knows a lot , but he never ________.

My neighbor is as ___as a young man and dislikes sitting around doing nothing all day．

the baby milk powder was found to be polluted,there has been universal doubt _____ other food products are safe _____.

The three sisters decided to hold a family party to ______their parents’ silver wedding (银婚).[ ]

_______you work,________grades you will get.