问题补充：
---Who called just now?
---I don’t know because I didn’t his voice.
A. listen
B. recognize
C. get to know
D. realize
答案：
A. listen
(答案→)B. recognize
C. get to know
D. realize
解析：句意：--刚才谁打电话了？--我不知道因为我没有听出他的声音。Listen听，强调听的动作；recognize听出，认出；get to know逐渐了解；realize意识到，实现。根据句意故选B。
