放射性核素肺扫描有助于下列哪项引起胸痛疾病的诊断（）
A.肺梗死
B.急性心肌梗死
C.主动脉夹层动脉瘤
D.肺癌
E.肺炎
参考答案：A
It is estimated that there are more than 40 universities in Britain--nearly ____ in 1960.
A．as twice many as
B．as many twice as
C．twice many as
D．twice as many as
辅酶在酶促反应中的作用是
A．起运载体的作用B．维持酶的空间构象C．参加活性中心的组成D．促进中间复合物形成E．提供必需基团
