Maple Goodman Teo,
Many already posted their answers. But I will give my two cent's worth anyway. This is what I would say:
1. I live in Taiwan now. But I am quite familiar with New York because I had lived there for five yeas before. Thefact that you did live in N.Y. for five years which was a long time, Iwould use past perfect. Simply because you left the city but you hadlived there.
2. I live in Taiwan now. But I am quite familiar with New York because I lived there for five yeas before.
# 2 is ok but “before” is not really necessary.
3. He lives in Taiwan now. He is not familiar with New York although he had lived there for five years.
4. He lives in Taiwan now. He is not familiar with New York although he lived there for five years. - acceptable
"For" and the past fact STRONGELY call for past perfecttense in my (you know, a student's) brain. Glad to read your comment,Goodman!
Hi Maple
There is nothing about the word 'for' that should suggest that you need to use the 'past perfect'. If that's a "rule" you've learned somewhere along the line, I
strongly suggest you try to "unlearn" it fast.
The word 'for' can be used with any tense -- no matter whether you're talking about the present, the past or the future.
The past perfect is typically used in order to place the time of one past activity further in the past than another past activity. The context in the sentences above contains the simple present tense (i.e. lives in Taiwan), and then something that happened before that present activity is mentioned (i.e. lived in New York). The simple past tense (lived) is just fine. The past perfect (had lived) is completely unnecessary because there is no mention of any other past activity.