long time可加s吗?

long time可加s吗? 1.不可数名词前有形容词可加冠词吗?可变复数吗?怎么变?for a long time;for long times对不 【改错】ten minutes is long long time.minutes应不应该加S It's a long time since …… 后加什么时态 是固定的吗 还是看情况 we have been best friends for a long time中friends为什么要加s so long a time为什么加a, it's a long time什么意思 long time no see.what's new? It's a long time ( ).选什么? It's raining for a long time? British英国人时可加s吗 spend some time, time 能不能加S