Listen to a conversation between a student and a counselor at the University Counseling Center.
请听一段学生和大学咨询中心辅导员之间的对话。
2
Listen to a conversation between a student and an employee at the student activity center.
听一段学生和学生活动中心员工之间的对话。
3
If the center of NGC 4258 were a star cluster, the stars would be so closely spaced that collisions between individual stars would have long ago torn the cluster apart.
如果 NGC 4258 的中心是一个星团，恒星之间的距离会非常近，以至于在很久以前单个恒星之间的碰撞就会把星团撕裂。