---How long has the meeting ?- Just a minute. I will check the time.A. begun B. started

问题补充：

---How long has the meeting ?

--- Just a minute. I will check the time.

A. begun

B. started

C. been on

D. been begun

答案：

A. begun

B. started

(答案→)C. been on

D. been begun

解析：句意：-会议开始多长时间了？-仅仅一分钟。我会核对一下时间。句子中how long是对一段时间来进行提问的，而begin 和start 都是瞬间性动词，不能与一段时间连用，故A、B、D可排除；be on 是一个系表结构的短语，可以持续，故选C。