根据短文内容的理解，判断正误。
Mr. and Mrs. Wilson and their children were going to begin their holiday one day, and they had to be at the airport at eleven forty in the morning. "It'll take us half an hour to get there in the car," Mr. Wilson said, "so we must leave before eleven o'clock. Don't be late."
At ten minutes to eleven, they were busy doing things, except Mrs. Wilson didn't, she was sitting quietly on a chair in the garden and enjoying the sun.
Her husband and children were very surprised. Why wasn't she busy, too. Mrs. Wilson answered, "Well, before I went to bed last night, I moved all our clocks and watches ahead twenty minutes. So now we can go to the airport quietly, Don't worry, then."
