B(2017·临海)

I was shopping in a big store when I saw a cashier(收银员) talking to a boy about 5 or 6 years old. “I'm sorry, but you don't have enough(足够的) money to buy this doll，” the cashier said.
The little boy turned to me and asked, “Uncle, are you sure I don't have enough money？” I counted(数) his money and said, “I'm sorry, but it's not enough, my dear.” Then I asked him who he wished to give the doll to. “My sister wanted the doll so much. I want to give it to her for her birthday. I have to give the doll to my mom so that she can give it to my sister when she goes there.” His eyes were so sad(伤心的) when saying this. “My sister is with God(上帝) now. Dad says that Mom is going to see God very soon too, so she can take the doll to my sister.” My heart(心) nearly stopped.
The little boy looked again at the doll with sad eyes, very quietly. I put some money into his money so quickly that he didn't see it. Then I said, “Let's count the money again.”
“I have enough money for the doll！” the little boy said excitedly. “Thank you, God, for giving me enough money！”
(　　)15. The little boy wanted to buy the doll for ________．
A. the writer　　　　 B. his mom
C. his sister　　　　 D. his dad
(　　)16. The boy got the doll because ________．
A. it was free
B. God gave it to him
C. the cashier bought it for him
D. the writer put in some money
(　　)17. We can know from the passage that ________．
A. the boy loved his sister very much
B. the writer knew the little girl before
C. the writer had a lot of money
D. the boy's dad went to see God
(　　)18. The best title(标题) of this passage is ________．
A. A Big Store
B. Little Boy and the Doll
C. A Mother with Great Love
D. A Helpful Cashier
15－18. CDAB