The custom of choosing a sweetheart on this date spread through Europe in the Middle Ages, and then to the early American colonies.
中世纪时，在这个日子里选择意中人的习俗传遍了欧洲，然后又传到了早期的美洲殖民地。
2
The opening paragraph invokes a vision of England in the earlyMiddle Ages.
头一段的引言描绘出中世纪前期的英格兰景象。
《牛津词典》
3
Children of educated and upper-middle-class parents turn out to be far more curious, even at early ages, than children of working-class and lower-class families.