D段：vertical movements; zooplankton/plankton; by night/ by day= during the night/day, (Often used in simultaneous clauses for contrast.); aphids; de`plete sth;
eg: By day, Mary worked in an office;by night, she took classes. Dave slept by day and worked by night.
So can the movement of aphids when, having depleted the young leaves on one food plant, their offspring then fly onward to a different host plant, with no one aphid ever returning to where it started.
E段：intricate; take off; appropriate VS appreciate; migration-migrational; wildebeest牛羚; tender adj.v. , at a tender age/ at the tender age of ;
F段：detrimental impact; resemble v. VS assemble; antelope n.羚; `mountainous; New World, 美洲大陆, Old World, 欧洲国家; one population n.2 族群 a particular group of people or animals living in a particular area; range 牧场, summer range; in/within range of sth/ out of range of sth; sagebrush, brush n.2 灌木丛;刷子; blow-blew-blown,吹, blown adj.开了花的;
eg: Here they wait out the frozen months, feeding mainly on sagebrush blown clear of snow.
wait sb/sth out sb/sth , to wait until sth happens or ends;
- wait somebody out also wait out somebody: to allow time to go past until someone does something
- wait out something also wait something out: to allow time to go past until something happens or ends