alternatev.交替；轮流adj.间隔的；轮流的；交替的n.代替者；供替代的选择alternate block转替部件alternate scour交替冲刷alternate works预备工事alternate paper备用稿alternate timer更替定时器alternate joint交错接缝,错缝,错列接头,错缝接合alternate field轮耕地alternate sweep交替扫描alternate entry交替进入, 交替输入alternate cover交替掩护