问题补充：
For some people, the sight of a mouse can be reason to scream. For other mice, the same sight can be reason to sing.
Mice will probably 21sing their way to any concert, but researchers in the United States have found 22that mice do, 23, sing.
Scientists already knew that mice make ultrasonic(超声波) sounds—noises that are too high-pitched(高音的) for people to hear 24special equipment.
To find out whether mice put such sounds together in song-like 25, the researchers recorded the sounds of 1 mice. Using computer 26, they were able to separate the sounds into specific types of syllables(音节), and found the mice produced about 10 syllables per second.
The results showed that nearly all of the mice repeated sequences(顺序) of syllables in different patterns. That’s enough to meet the definition of what scientists 27song. But not all scientists are 28 _ that what the mice are doing is 29singing. To prove it, the researchers must show that there’s learning involved. And, they need to 30why the mice sing.
21. A. almost B. even C. never D. usually
22. A. coincidence B. evidence C. guidance D. instance
23. A. at once B. by means C. for example D. in fact
24. A. during B. inside C. through D. without
25. A. fashions B. instructions C. patterns D. styles
26. A. access B. printer C. screen D. software
27. A. call B. hear C. sing D. write
28. A. accustomed B. convinced C. involved D. qualified
29. A. actually B. obviously C. simply D. unlikely
30. A. figure out B. get about C. run across D. talk over21-30 CBDDC DABAA
答案：
(答案→)21-30 CBDDC DABAA
解析：
导读：这是一篇科普文章，文章讲到科学家对于老鼠进行研究，从中发现他们也有自己的音律表达。
21. C。考查副词词意辨析和语境的理解。从语篇知道老鼠开音乐会那是从来没有的。
22. B。考查名词词意辨析和语境的理解。由上下文知道在美国的研究者找到老鼠唱歌的证据。
23. D。考查介词短语辨析和语境的理解。这里是说发现老鼠事实上也会唱歌。
24. D。考查介词词意辨析和语境的理解。表示没有特殊的设备人类听不到老鼠所发出的音律。
25. C。考查名词词意辨析和语境的理解。研究者在研究是否老鼠能够把声音结合在一起构成像歌曲一样具有节奏。
26. D。考查名词词意辨析和语境的理解。运用电脑软件来寻找节奏。
27. A。考查动词词意辨析和语境的理解。研究者发现它们的声音可以组成有节奏的东西，这些证据可以符合歌曲的定义。
28. B。考查动词词意辨析和语境的理解。表示并非所有的科学家都相信老鼠会唱歌。
29. A。考查副词词意辨析和语境的理解。表示“事实上”，即有写科学家不相信老鼠真的会唱歌。
30. A。考查动词词组辨析和语境的理解。figure out计算出, 解决；get about走动, 旅行, 传开；run across偶遇, 跑着穿过；talk over详尽地商议, 商量, 讨论, 说服。下一步科学家们要解决的问题是为什么老鼠要唱歌。
