心肌最发达的是（）。
A.右心室
B.左心房
C.右心房
D.左心室
E.以上均是
参考答案：D
—Excuse me , Sir . But smoking is not allowed here.
—Sorry, I didn’t see the sign. I’ll _______ my cigarette at once. [ ]
A. put out
B. put away
C. put up
D. put off
关节鼠
