医生建议避免在没有防护的情况下长时间暴露在直射阳光下。

Doctors advise against ___prolonged exposure to direct sunlight without protection.

让我们惊讶的是我们在希思罗机场起飞时不得不忍受的长时间延误。

What surprised us was the ___prolonged delay we had to suffer during our departure from Heathrow.

旷日持久的外交谈判最终促成了一份历史性的和平条约。

The ___prolonged diplomatic negotiations eventually led to a historic peace treaty.