he has been working so hard . __________ he could answer such a difficult question.

A．No wander

B．No wonder

C．why

D．because

男性，28岁，汽车司机，前胸撞于方向盘上，伤后约1h。查体：意识清，脉搏130/min，奇脉，血压90/80mmHg，呼吸32/min，颈静脉怒张，心浊音界扩大，心音弱，两肺呼吸音正常，诊断可能性最大是（）

A.闭合性气胸

B.张力性气胸

C.肺挫伤

D.血胸

E.血心包