as brave as a lion字面意思像狮子一样勇敢，引申为非常勇敢；勇猛如虎。

【例句】
He may be small and not very strong, but he's as brave as a lion.
他个子或许矮小，身体也不够强壮，但非常勇敢。

Puny though he looked, he was as brave as a lion.
虽然他看上去弱小，但却十分勇敢。