首先不能那样判断哦,用什么做主语取决于你要问的是什么.这是两个特殊疑问词组,都是问时间的,
How long 多久,多长时间:
1 —How long is the bridge?(这句如果the bridge上文提到过,就可以这样问:How long is it )
— It’s 500 metres.
2 —How long did he wait for you here?他在这儿等了你多久?
—For two hours.两个小时.
3 —How long did it take him to finish his homework?他用多长时间完成的他的家庭作业?
—It took him 20 minutes to finish his homework.他用了20分钟完成的他的家庭作业
4 _How long are you feeling like this?像这样已经多久了?
_Since last night.从昨晚到现在.
How soon通常问一般将来时,意为:多块,多久才能……?"
1 How soon will you arrive here?你们多久才能到达哪里?
2 —How soon can you finish the work?还要多久你能完成这项工作?