adj.无痛的；不痛的
The scan is safe, quick and painless. 扫描过程是安全、快速和无痛的。
The most common presenting symptom is a painless mass. 主要的临床症状为无痛性肿瘤。
Walking is an easy, painless and powerful form of exercise. 走路是一种简单、不痛苦又有效的运动。
adv.(口语)不难地；不费力地
