He has failed for several times in making the experiment, but he's been keeping his chin up. 误译：他在做实验时已经失败了好几次，但他一直保持着抬头。 正确：做这个实验他已几经挫折，但他毫不气馁。 说明：keep one's chin up 的意思是“在困难环境下仍然乐观；毫不气馁”。