慢性肺源性心脏病最常见的病因是
A．神经-肌肉病变
B．严重的胸廓畸形
C．慢性支气管炎和结核病
D．肺血管疾患
E．睡眠呼吸暂停综合征
参考答案：C
西周时为巩固对周边的统治，实行了“授民授疆土”的 [ ]
A．禅让制
B．世袭制
C．分封制
D．宗法制
The reason _____ so many people are crazy about Gangnum Style is _____ it’s good for bodybuilding, and it brings people a lot of fun.
A．/; that
B．that; because
C．why; because
D．why; that
