单词学习：failing 名词/介词
failing
/ˈfeɪlɪŋ/
n. 缺点，弱点；失败，未能做到；prep. 如果没有，若无
Failing to prepare for the class, Mr. Gu had to improvise his lecture.
由于没有为课程做准备，顾老师不得不即兴讲课。
单词卡片
卡片已就绪
