"i have been for a long time"中,"have" 为什么不用"had"?

"i have been for a long time"中,"have" 为什么不用"had"? We have been waiting a long time.不用for a long time I have been chasing for a long time I have been loving you for a long time i have been here for a long time 句子I knew him for a long time为什么不用 have known用knew? we have been best friends for a long time中friends为什么要加s sharks have been around for a very long time.这句话中为什么有around? We have been good friends a long time.这里的a long time之前不用加for I have been away for a long time等于I____a long time_____. Heiio stranger.I have been waiting for you for a long time.A l have been looking for someone for a long time