选择：
Put the books back () the bookcase,Tom.
A.behind
B.on
C.of
D.under
Look!Who is () over there?
Mr.smith.Our new teacher.
A.this
B.that
C.无
D.these
补全句子：(首字母已给出)
What do you want to buy?You can make a (l-).
Peter has no brother or sister.He is the (o-).