3箱苹果共计135元，照这样计算．买12箱苹果共需多少元？
135÷3×12，
=45×12，
=540（元）．
答：买12箱苹果共需540元．
The pilot asked all the passengers on board to remain ______ as the plane was making a landing.
A．seat
B．seating
C．seated
D．to be seating
企业原材料仓库的收料单属于（）。
A.外来原始凭证
B.自制原始凭证
C.付款凭证
D.转账凭证
