端坐呼吸最常见于（）
A.代谢性酸中毒
B.慢性支气管炎
C.肺叶切除术后
D.充血性心力衰竭
E.肺气肿
参考答案：D
—Where is Tom? We can’t find him anywhere.
—Perhaps he_____ home.
A．has gone
B．is going
C．went
D．was going
试述脊柱的组成及其生理弯曲。
