英语选择题（请说明选择理由）

英语选择题（请说明选择理由）
1.The teacher has just graduated from school,so he is ____to his work.
A.old B.young C.polite D.new
2.—How do you go up and down the high building?—We use________.
A.a ladder B.a line C.an elevator D.foot
3.—How much does the book_____?—About eight dollars.
A.spend B.cost C.take D.pay