Tom walked into a shop.It had a sign (招牌) outside:“ Second-had(旧的) clothes bought and sold.

Tom walked into a shop.It had a sign (招牌) outside:“ Second-had(旧的) clothes bought and sold.
He was carrying an old pair of trousers and asked the owner of the shop.“How much will you give me for these?” The man looked at them and then said,“ Two dollars(美元).” "What!" said Tom."I had guessed they were worth(值...价钱) at least(至少) five."
"No," said the man,"they aren't worth a cent(美分)more than two dollars."
"Well," said Tom.Taking two dollars out of his pocket,"here's your money.These trousers were hanging outside your shop.The list price(定价) of them was six dollars and a half."But I thought that was too much money,so I wanted to find out how much they were really worth."
Before the shop owner could think of anything,Tom walked out of the shop with the pair of trousers全文翻译,请问tom是干吗的