He weighed in with a Latin quotation.

他引用了一条拉丁文成语。

Never too Old to Learn is an idiom.

'活到老学到老'是句成语。

He has a great number of English idioms at command.

他掌握了大量英语成语。

Abstract: Generally speaking, idioms include proverbs, phrases, vulgarism and two-part allegorical sayings.

从广义上来，习语包括成语、谚语、语歇后语等。