are加動詞ing是什么時態(tài)

　　We are very sad to hear that you are leaving.

　　聽說你要走了，我們十分難過。

　　Here are two records that are bubbling under.

　　這兩張唱片將會走紅。

　　What are you doing? Are you out of your mind?

　　你在干什么？你瘋了嗎？