I didn’t know he came back I met him in the street . A. since B. whenC. untilD. after

问题补充：

I didn’t know he came back I met him in the street .

A. since

B. when

C. until

D. after

答案：

A. since

B. when

(答案→)C. until

D. after

解析：本题的含义是直到我在街道上碰到他，我才知道他回来了，not ……until表示直到……才的含义，故本题选C。