录音机磁头磨损后将使声音(),录音失真度增大,甚至无声。
A.变小
B.变尖
C.变粗
D.变大
参考答案:A
白化病为隐性遗传病,在某白化病患者的体细胞中,控制白化病的基因组成是[ ]
A.AA
B.aa
C.A
D.a
Over a very large number of trials, the probability of an event ________ is equal to the probability that it will not occur.
A.occurring
B.to occur
C.occurs
D.occur