--Your Japanese is so good. How long have you been in Japan?-- I was five.A. SinceB. Befo

问题补充：

--Your Japanese is so good. How long have you been in Japan?

-- I was five.

A. Since

B. Before

C. Until

D. When

答案：

(答案→)A. Since

B. Before

C. Until

D. When

解析：Since自从……以来；Before 在……之前；Until直到；When当……时。句意：你的日语这么好。你在日本多久了？结合语境可知选A，自从我五岁以来。