最近，全世界都在等待英國的凱特王妃生二胎的消息。根據(jù)英國修改后的《王位繼承法》，第二胎無論是男娃女娃，都會成為“備胎繼承人”。

In royal families, the crown goes to the oldest child. That's the heir. The "spare heir" is the next child who would ascend the throne should something happen to the heir. In the UK, when William becomes King, Prince George is the heir. His brother or sister, who will be born in April, will be William's spare heir. Harry was the spare heir until Prince George was born.

在王室中，王位傳給長子，稱作王位繼承人。如果王位繼承人發(fā)生不測，下一個繼承王位的人叫做備胎繼承人。在英國，當威廉王子成為國王時，喬治王子就是王位繼承人，而即將在4月出世的二胎，無論男女，都會成為威廉的備胎繼承人。在喬治王子出生之前，威廉的弟弟哈里王子一直是備胎繼承人。

For example:

Aristocratic wives were once told they needed to provide an "heir and a spare heir" at least.

貴族的妻子們曾經(jīng)被教導要至少生一個繼承人和一個備胎繼承人。

（中國日報網(wǎng)英語點津 江巍 ）