问题补充:
This interesting book only me ten yuan and I ten month reading it.
A. cost, spend
B. cost, spent
C. spends, cost
D. spent, costs
答案:
A. cost, spend
(答案→)B. cost, spent
C. spends, cost
D. spent, costs
解析:spend主语通常为人表示花费的意思,故不选CD,本题表示的是过去用过去时态,cost的过去式是cost,spend的过去式是spent,故本题选B。