external pH细胞外pHexternaladj.外来的；外部的；外面的；表面的n.外观；外部；外界事物external examination由校外人士主持的考试external irradiation外部照射,外辐照external wall cracks外墙裂缝external power relay外力继电器external congenitals宗筋； 积筋external-structure外部结构external accelerator外置油门external contour saw外轮廓锯法external penetration渗漏external clutch gear离合器外齿轮