for long[usually in questions and negatives] for a long time 长久地,长期地 Have you known them for long? 你认识他们很久了吗?
I haven’t seen her for so long that I’ve forgotten what she looks like. 我很久没有见到她,都已经忘记她的样子了。
for long• Have you been working here for long?• Have you known the Garretts for very long?• He'll have to stay in hospital, but not for long.• I haven't known them for very long.• I hope his speech doesn't go on for long.
→ for long at long2(1)