D．To gather materials for his literary creation.

　　解析：选D　推理判断题。根据第三段可知，Clarke在他的一本书里涉及了Mathews的电子音乐技术。由此可推知，Clarke主要是为文学创作获取素材才去Bell Laboratories的。

　　29．What electronic music tools did Mathews create?

　　A．Something used to record live music.

　　B．Something used to create special sound.

　　C．Something used to improve computer music.

　　D．Something used to create computer music.

　　解析：选C　细节理解题。根据第五段可知，制作计算机音乐时，Radio Baton可以用来控制管弦乐的速度、声级等，能改进音乐。

　　30．What does Mathews think of his Music?

　　A．It is more pleasant to the ear.

　　B．It can help make more sounds.

　　C．It will finally replace the violin.

　　D．It is more popular than live music.

　　解析：选B　细节理解题。根据最后一段可知，一般小提琴发出的声音就是那一种，用Mathews的Music可以让它的声音有无数种，即他的Music能帮助发出更多声音。

　　31．What can we learn about Mathews?

　　A．He is the father of computer music.

　　B．His creation succeeded on the first try.

　　C．He wrote Music to replace instruments.

　　D．He changed the functions of computers.

　　解析：选A　推理判断题。根据全文可知，是Mathews首先创造了计算机音乐，并进而发展出一系列与音乐相关的电子产品，在音乐界掀起了一场革命，故他是计算机音乐之父。

　　D

　　(2018·湖北省鄂西北联考)It happens to most first­time fish keepers. They run to a fish store, pick out the best­looking fish, and get all the things they need for their tanks. Then they fill up their tanks and put their fish in the water. Over the course of the next week, their fish aren't looking so good. Then all of a sudden, all of their fish start to die off.

Luckily, there is an explanation. Ammonia (氨) and nitrite (亚