have been doing是什么时态

　　例句：

　　I have been waiting for you for almost 2 hours.

　　我一直在等你，快两个小时了。

　　Where have you been hiding?

　　你都跑到哪去了？

　　Who has been making trouble?

　　是谁一直在捣乱？

　　We have been looking all over for you.

　　我们到处在找你。