单项选择题

In astronomical terms, a cluster ______.

A．consists of galaxies
B．makes up superclusters
C．consists of groups
D．makes up a group

<上一题目录下一题>

热门试题

填空题

What does the author mention as a cause of changes in the role of child in the United States

填空题

What caused the parents’ increasing interest in the techniques of raising child