大学英语：you have probably been learning independently

 … you have probably been learning independently, actively, and purposefully.

　　句中所用的时态为现在完成进行时，表示一个动作从过去的某一时间开始，一直延续到现在，可能还要继续下去。又如：

　　1) He has been working for a whole day.

　　2) They have been watching TV for two hours.

　　请翻译下面的句子：

　　1) 老李已经在南京生活了二十年。（Lao Li has been living in Nanjing for 20 years.）

　　2) 雨下多久了？（How long has it been raining?）

　　3) 我等了他一个多小时了。（I have been waiting for him for more than an hour.）