购买单价为a元的作业本n个,付了b元,应找回( )元 [ ]
A.(b-a)
B.b-n
C.na-b
D.b-na
答案:D
读句子,填空。
1. I can't find _____________ toothbrush.
_____________ toothbrush is lost.
2. She can't find _____________ teddy bear.
_____________ teddy bear is lost.
3. They can't find _____________ car.
_____________ car is lost.
4. _____________ can't find your key.
_____________ key is lost.
图书借阅过期未还者按每天每册()收取滞纳金。
A.0.1元
B.0.2
C.0.5元