[译] 那个癌症病人暂时感到不疼了。
[误] The patient suffering from cancer doesn't feel painless for the time being.

[正] The patient suffering from cancer doesn't feel any pain for the time being.
[注] 表示"（人）不感觉疼痛"，应该说 feel no pain, 而不能说 feel painless。painless 表示"不痛的"，与 painful 一样主语不应该是人，而且通常用作定语，如 painless extraction（无痛拔牙），painless surgery（无痛手术）等。