可: approve选: select; choose; pick的: 4次方是 The fourth power of 2 i ...可选的(配件): optional必选或可选的: mandatory or optional设置可选的层: set selectable layers可选的(用于帧格式): o optional设置可选的类型: set selectable types设置可选的属性: set selectable attributes设置可选的颜色: set selectable colors任选的预约时可选业务: optional subscription-time selectable service实现一个可选的注解机制: implementing an alternative annotations mechanism可选的(注册时出现表示该格不一定要填): optional可选: optional; pal; trr被选的: chosen; elect分选的: assorted; sorted风选的: winnowed候选的: candidate获选的: co-optative精选的: of choice; selected; well-chosen任选的: arbitrary; optional手选的: hand-picked首选的: preferred所选的: selected挑选的: picked