伸膝关节的主要肌肉是（）
A.臀大肌
B.股二头肌
C.肱三头肌
D.股四头肌
E.肱二头肌
参考答案：D
—Peter, is there anything else you want to know about China?
—Yes, I am stll wondering __________ .[ ]
A. how is Chinese paper cut made
B. how was the Great Wall built in ancient times
C. why the Chinese people like to play the dragon dance
D. why do the Chinese people eat rice dumplings at Dragon Boat Festival
为了（）的需要，基坑开挖深度甚至超过30米。
A、技术
B、施工
C、满足结构稳定和开发地下空间
D、经济
