请根据Amy和Bob的对话完成信息。

Amy: Hi, Bob! What are you reading?

Bob: I am reading a book named "Success Stories."

Amy: What is it about?

Bob: It's about successful people. It records their success stories.

Amy: Is it written by a Chinese writer?

Bob: No. By an American writer in English.

Amy: What do you think of the book?

Bob: It is very good. The stories make a strong impression on me.

Amy: Oh, I am preparing for a talk about successful people.

         Can you lend me the book?

Bob: Sure.

     Amy and Bob are talking about a 1______ named "Success stories".

It is written by an 2______. It is not written in Chinese but in 3_____.

The book contains success 4______ of some people. The stories make

a strong 5______ on Bob.

土地、劳动、资本都是经济增长不可或缺的生产要素，均构成经济增长的源泉，但在上述投入要素数量既定的条件下，( )是经济持续增长最根本的源泉。

A．技术进步

B．提高要素生产率

C．提高劳动生产率

D．提高环境质量

E．提高土地使用率