学生参加重考的次数将受到限制。Limits will be placed on the number of exam retakes students can sit.他坚持要求老师重考.He persisted in asking his teacher to retake the test....
蓝光的波长比红光的短。Blue light has a shorter wavelength than red.广播1台已经用这个波长广播多年了.Radio One has broadcast on this wavelength for years.当局无法干扰这一波长.The authorities were unable to jam this wavelength....