女性，20岁，车祸后2小时，呼吸困难。查体：右侧呼吸音消失，叩鼓音，皮下气肿，右胸中部骨摩擦音，气管居中。考虑为()

A．肋骨骨折合并开放性气胸

B．肋骨骨折合并张力性气胸

C．肋骨骨折合并闭合性气胸

D．肋骨骨折合并血胸

E．肋骨骨折合并心脏损伤

The achievements of the greatest minds in science could never have been reached if it had not been for the patient and accurate work of hundreds of other people.

A．has it not been

B．if it had been

C．if hasn't been

D．had it not been