five years is/are

【问】 ×Two weeks are enough for a nice vacation.这是托福试题中的一道改错题。请问句中的动词are有什么错误?

【答】 表示时间的名词短语有时在概念上被看成是一个时间单位或时间段，故后面接单数动词，也就是说，这里起作用的是概念一致的原则：

1. Fifteen years represents a long period of his life. (CGEL)(fifteen years 在概念上表示that period)

十五年表示他生命的一个很长的时期。

2. Five hours isn’t enough.

五个小时是不够的。

3. A hundred years is called a century.

一百年叫做一个世纪。

4. Two hours is the limit of this test.

两小时是这次考试的时限。

5. A number of years passes. (English for Today)

许多年过去了。

请做下面的英语试题：

1. “How many days?” “Did you say that five days____required to complete the work?”

(A) are (B) were (C) was (D) is

2. Fifteen minutes are all that I can spare to talk over this matter with you. (EPT 教程)

(参见minutes is/are)