The teacher developed a social studies unit on ancient civilizations to enhance students' understanding of history.
老师开发了一个关于古代文明的社会学科教学单元，以增强学生对历史的理解。
Students were required to complete a social studies unit on environmental issues as part of their curriculum.
学生被要求完成一个关于环境问题的社会学科教学单元，作为课程的一部分。