北京人过着群居生活的主要原因是
①血缘关系的结合 ②工具简陋粗糙 ③人们头脑简单 ④生活环境险恶 [ ]
A．①②
B．③④
C．①③
D．②④
答案：D
There are _______ unusual series of facts that everyone wants to ________all of them.
A．such many; settle down
B．such much; settle down
C．so many; set down
D．so much; set down
