上课前体育老师鸣哨的意思是什么？
参考答案：
集合整队
--- Everybody is playing outside. Can I join them, Mom?
--- _______ Not until you have finished practicing the piano.
A．Why not?
B．Will you?
C．I hope so
D．I’m afraid not.
胸膜转移瘤最常见的并发症是（）
A.发热
B.胸腔积液
C.声音嘶哑
D.吞咽困难
E.心律失常
