phaseable mark

例句：

1. 1.The phaseable mark on the wall indicates that it's a door.
   墙上的可阶段标记表明它是一个门。
2. 2. The phaseable mark on the map shows the location of the campsite.
   地图上的可阶段标记显示了露营地的位置。
3. 3. The phaseable mark on the road sign indicates that there is a turn coming up.
   路标上的可阶段标记表示即将转弯。