■ virtue

1) 作为不可数名词，virtue 不加任何冠词，概括笼统地表示“崇高的道德”。

• a man of virtue一个有道德的人
• Virtue is its own reward.有德者不望报。

2) 但是作为可数名词，意思是具体的某一件德行。

• Kindness is a virtue.与人为善是一种德行。

3) 转用到非人的事物上，virtue 可以代表该事物笼统的“有好处”和“功效”（不可数）或者一个具体的优点（可数）。

• There is no virtue in what he says.他所说的没有什么可取之处。
• A medicine of dubious virtue.功效不怎么样的药物。
• The virtue of this drug is temporary.这种药物的功效是暂时的。
• The main virtue of steel is its strength.钢的主要优点就是结实。
• Mr. Long's speeches have the virtue of being brief.朗格先生的讲演，优点就是简短。
• The virtue of this sewing machine is that it needs so little repair.这种缝衣机的优点，就是它不大需要修理。

4) to make a virtue of necessity 是个成语（原意是把 necessity 变为 virtue），意思是“本来做某事是迫不得已，但将计就计，顺水推舟，把坏事变好事”。

• Once the mayor was forced by the voters to cut his budget, he made a virtue of necessity and loudly denounced government spending.本来市长是被选民们逼着削减预算的，但他将计就计，大声疾呼抨击政府开支过多。
• It's a long way to drive so I thought I'd make a virtue of necessity and stop off at some interesting places along the way.有一大段路要开车，于是我就想，我可以顺水推舟，沿路开到某些有意思的地方就停一下。