选D；
如果答句中用的介词如果是in,前面要用how soon.如in an hour, in two weeks 等.
后面如果是：in a year,一年后,那用 how soon.
how soon意为“还要多久”,是对从某个基本时间到将来某动作结束或某动作发生这段时间提问,常用在一般将来时态的句子中,其答语通常是“in + 一段时间”.
—How soon can you finish the work? 还要多久你能完成这项工作?
—In half an hour. 半小时后.
例：选择填空.
1.— _______ did the meeting last? —About half an hour.
A. How soon B. How long C. How far D. How much
2.— _______ will Ezhou-Huanggang Bridge be finished? —In a few months.
A. How soon B. How long C. How often D. How far
第1：B
第2：A