adj. 长期的（持久的）；长时间；好久好久
of long duration
同义词： longtime(a)
...mes（有时）、（c）With the times（随着时代）都不是本句想要表达的意思，也都不通顺，因此不正确；（d）A long time（长时间）没有介词for，不能作时间状语，也不正确；只有（b）After a time（一段时间以后）最符合题义，所以（b）是正确。
大欢同志很有教师范 » There is a big however comrade teacher fan 好久好久 » Long time 我要为我的女儿一条橙色的裙子 » I would like to be my daughter orange skirt ..
留住长长久久(Long time)的回想。再也不会随工夫的耽误而垂垂被吞没。
They took a long time to mend the roof.
他们花了好长时间修缮房顶。
I waited a long time for him to return.
我等他回来等了很长时间。
It's been such a long time since I played.
自从我上次演奏以来已经过了这么长时间了。
The song is about leaving the big city for the countryside, going home again after a long time away.
VOA : special.2009.11.09
And the Aristotelian view held for a long time, but eventually it started to crumble in the light of more data.
而亚里士多德的观点在很长时间里得到了认同，但最终还是崩溃了,在越来越多的数据面前。
固态化学导论课程节选 : 麻省理工公开课
I don't know if you know this, but for a long time when movies took place in New York,
我不清楚你是否知道，很长一段时间，电影里发生在纽约的场景，
SpeakingMax英语口语达人 : 电影里的中央车站
For the best results, carrots should be grown in sandy soil that does not hold water for a long time.
VOA : special.2009.02.24
Many people believe Pat Summitt's winning record will not be reached by another college basketball coach for a long time.
VOA : special.2009.03.20
Mr. Gray's death was the breaking point, but it was a long time coming.
The implication being that they will forfeit co-operation with Russia for a long time ahead.
Or at least easier and more affordable than it has been in a long time.