My dear sirs, you are right, that is just what we are.

可爱的先生们, 你们讲对了, 我们正是这样.

Dear Sirs and Madams, we are going to take off soon.

尊敬的女士们先生们，飞机马上就要起飞了。

Use Dear Sirs, if you are writing to more than one person even if the group of people includes women.

如果你写邮件给两个或以上的人，即使这些人里有女士，请写“尊敬的先生们”