But daily verticalmovements by zooplankton in the ocean—upward by night to seek food, downward by day to escape predators—can also be considered migration.
但是海洋中浮游动物每天的垂直运动——夜里上浮以寻找食物，白天下潜以躲避捕食者——也可以被视作迁徒。
2
In the process of playing the piano, there should be a harmonious unity between relaxation and concentration, between dropping and supporting, between horizontal movements and verticalmovements.
钢琴弹奏过程中，放松与集中，下落与支撑应有机统一，水平运动与垂直运动应协调配合。
3
Some movements involving primarily vertical or horizontal motions of the body as a whole, in which rotations can be ignored, can be studied using simple equations of linear motion in three dimensions.