Why do medicines expire after a certain period of time?

一段时间后，药物为什么会过期？

Does your current lease allow you to request that your tenant vacate within a certain period of time?

您当前的租契是否允许您对您的房客提出在某一段时间之内搬出的要求？

In 1959, the swindle of coffee in Costa Rico paralyzed the country's economy for a certain period of time.

哥斯达黎加发生的咖啡诈骗案一度使该国经济陷入瘫痪状态。

If the processor hasn't received any input for a certain period of time, it turns off the monitor.

如果处理器有一段时间没有接到任何输入的话，就会把显示器关掉。

Encountered after a certain period of time when the owner is still not forget the expression of a sense of gratitude.

过一段时间后再遇到主人时，仍不要忘记表达感激之情。

Small businesses started by the unemployed urban dwellers are immune from taxes for a certain period of time.

城市失业人员经营小本生意在一定时间里可以享受免税待遇。

If you keep your money in the bank for a certain period of time, you can get a higher interest rate by buying a savings certificate.

假如你购买了一张储蓄存单，把钱存放在银行一段时间，你就会得到较高的利率。

When a customer is not satisfied with a product, he is entitled to return it to the store and get refunded during a certain period of time.

顾客有权在一段时间内退货，如果期限已过，也可以换货。 段中be entitled to表示有权利做某事，refund表示退款。

These above-mentioned no one is the lack of mind, but this does not prevent them in a certain period of time to make the wrong choices in life.

以上所说的这些人没有一个是缺乏头脑的，但是这并没有避免他们在一定时期内做出错误的人生选择。

So-called bonds, is the issuer to issue in accordance with legal procedures, and agreed in a certain period of time servicing the portfolio.

所谓的债券，是发行人在发行依照法定程序，并在一定时间内提供服务的协议投资组合。