题目内容：

1.Can you give us more example（example变不变复数?为什麽?)
2.Chemistry is Grace`s favorite subject at school 变同义句 Grace like chemistry best at school(like加不加s?为什麽?)
3.She was having a conversation with our teacher (conversation加不加s?为什麽?)
4.什么是第三人称?我只知道it ,she ,he,请举几个例子
5.Are the old people siting under the tree you panents?(为什么是Are,为什麽不是Is?)