X线上，在心膈角发现团状阴影，最常见的是（）
A.支气管肺炎
B.心包脂肪垫
C.麻疹肺炎
D.心包囊肿
E.心包憩室
参考答案：B
— Mum, must I stay there the whole day?
— No, you _____. You _____ come back after lunch, if you like. [ ]
A. mustn't; can
B. needn't; must
C. needn't; may
跆拳道比赛场地有几名裁判员？（）
A.1
B.2
C.3
D.4
