The dogs were most interested.

我们家的狗狗们是最感兴趣的。

What are they most interested in?

他们对什么最感兴趣？

What I am most interested in is American movies.

我最感兴趣的是美国电影。

American brand they are most interested in owning: tiffany.

最想拥有的美国品牌：蒂芙尼(Tiffany)。

What are ornithologists on Twitter most interested in this week?

Twitter上的鸟类学家本周最关心什么？