20-12NA 文法 Q5

该题考察开头
通过they record,  the scientists measured ...可知讲的是做实验，通过合并句子题中的 how consistent and patternd the beats were 说明敲击有规律的，D选项正确
A选项讲evolution of music，无关  
B选项讲mating，无关  
C选项讲tools，无关