勇气和愚蠢之间只有一线之隔。

There's ___a ___thin ___line between courage and foolishness.

在某些情况下，建设性批评和个人攻击之间只有细微差别。

In some situations, ___a ___fine ___line separates constructive criticism from personal attack.

许多人认为，爱与痴迷之间只有一线之隔。

Many argue that ___a ___thin ___line exists between love and obsession.