zài / xīn / lǐ / xué / kè / chéng / zhōng / lǎo / shī / jiè / shào / le / lì / tā / xíng / wéi / duì / shè / huì / hé / zuò / de / zuò / yòng在心理学课程中,老师介绍了利他行为对社会合作的作用。In the psychology class, the teacher explained how altruistic behavior supports social cooperation.