---How long is it we last met?About five years. You haven’t changed much.A. beforeB.

问题补充：

---How long is it we last met?

--- About five years. You haven’t changed much.

A. before

B. since

C. when

D. that

答案：

A. before

(答案→)B. since

C. when

D. that

解析：连词辨析。Before在……之前；since自……以来；when当……时候；that，那个引导限制性定语从句。根据题意，根据下文，大约五年了，你没多大变化。可知上文要表达的意思是，自从我们上次见面有多久了？故选B。