把下面句子变成一般疑问句（英语的 ）
1.Our teacher is over there.
2.They're at home.
3.We're inRow One.
4.I'm an American.
将下列句子变成复数句
1.This is a book.
2.That isn't an eff.
3.Is this a book?Yes,it is.
4.Your picture is very good.