external fan外风扇externaladj.外来的；外部的；外面的；表面的n.外观；外部；外界事物external diseconomy of production生产的外在不节约因素External prestressed bundled bars体外预应力束external-standard channels ratio外标准道比external quality assessment scheme室间质量评价external debt standstill agreement外债延期偿付的协议external prestressed strengthening体外预应力加固external circular grinding machine外圆磨床external thalamic medullary lamina丘脑外髓板external synchronous input adapter外部同步信号输入转接器external hyperpolarizing potential外超极化电位