If I have to take exams, this is the stage when I would prepare in earnest for them.

如果我有必要参加考试，这个阶段是我会认真准备考试的时候。

I could tell she spoke in earnest.

我看得出她是郑重其事地说的。

Campaigning will begin in earnest tomorrow.

活动明天正式开始。

The race for the White House begins in earnest today.

为入主白宫而展开的竞选今天正式开始。

The work on the house will begin in earnest on Monday.

这栋房子的修建工作将在星期一正式开始。