he wanted to know the exact time__the meeting would begin.A.

he wanted to know the exact time__the meeting would begin.A.that B.when 选A 还是B?为什么?个人倾向于选B,但答案是A,很疑惑.

答案是错误的.肯定是错误的.
选B
解析：这个题考查的是定语从句
1.定语从句（Attributive Clauses）在句中做定语,修饰一个名词或代词,被修饰的名词,词组或代词即先行词.定语从句通常出现在先行词之后,由关系词（关系代词或关系副词）引出.
2.先找先行词 是the time.
3.分析先行词在从句中充当什么成分.从句the meeting would begin 属于“主语+不及物动词”的基本句型.所以从句的主干成分不缺,就不再考虑关系代词that（that在从句中要充当主语,宾语,或表语）.也就是说,先行词the time在从句中做了时间状语,所以使用关系副词when.