详细解释:a. 无痛的, 不痛的
【医】 无痛的
词型变化：
名词:painlessness副词:painlessly英语解释：
形容词 painless:
requiring little hard work or exertionnot causing physical or psychological pain例句：
An instrument that in a painless and noninvasive manner uses the differential transmission and reflection of ultrasonic waves to create a detailed visual image of the brain.超声波心动描记器一种用来显示详细的大脑图象的仪器，利用超声波发送和反射的差异来测试并无伤无痛