问题
单项选择题
You should know better than______your little sister at home by herself.
A. to leave
B. leaving
C. to have left
D. left
答案
参考答案：A
解析： 句意：你应该知道，不该把你小妹妹一个人留在家里。to know better than to do sth．是一个常见的表示责备的句型，意为“明事理而不至于做某事”。