1. (2022高三上·月考) 阅读下面短文，从短文后各题所给的A、B、C和D四个选项中，选出可以填入空白处的最佳选项。

Children know the difference between right and wrong before they reach the age of two, according to new research1recently.

Scientists have2that babies aged between 19 and 21 months understand fairness and can3it in different situations. They say it is the first time that having a4of fairness has been identified in children at such a young5.

Researchers say babies will watch a 6 for longer if they think it contains something unfair, so in two experiments the babies were7on how long they watched a live scenario(情景)about fairness.

In the first, 19-month-olds8two giraffe puppets(玩偶) given either a toy each or both toys to one of the giraffes. Longer looking times9that something was unusual or10to the baby. In this experiment, three-quarters of the babies looked longer when one giraffe got11toys.

In a second experiment, two women 12each other with a pile of small 13 between them and an empty plastic box in front of each of them In one scenario, one woman 14put the toys away, while the other kept playing, but both women were given 15. In another scenario, both women put the toys away and both got a reward. The 1621-month-old babies looked reliably 17when the worker and the slacker(偷懒的人) were rewarded equally.

Psychologist Stephanie Sloane, who led the study at Illinois University, said:" We discovered that 19 and 21-month-old babies have a general18of faimess, and they can apply it 19to different situations. "

The20appear in Psychological Science, a journal published by the Association for Psychological Science.