fill up gaps in one's theory;give a satisfactory explanation of what one has said or done;justify oneself(/one's argument/one's case/one's position/one's views);keep one's story strajght;make one's case sound plausible(/tenable/coherent);make one's statement consistent(/valid);make out a good case(for oneself)
❍ 他为自己的错误编造了一点理由，但不能～。He made up an excuse for his mistake but COUId not justify hiscase.
自圆其说
tenable;logical;plausible;hold water;make valid (or plausible);justify oneself
这是不能～的。This assertion can not hold water./不能～ cannot offer a tenable argument; cannot justify oneself; cannot make one’s state ment valid;This is not a plausible explanation;This is a flimsy explanation.
自圆其说zì yuán qí shuō
圆：圆满，周密。形容找理由来掩饰自己的论断或谎言没有破绽。justify oneself, sound convincing, patch up the breach oneself, explain oneself