1.validity n．有效性；合法性(state of being legally acceptable)；正确性(state of being right)
词根记忆：来自valid(a．有效的，合法的)
例：The validity of a new scientific finding was questioned by most scientists.
2.vanish v.消失(to pass quickly from sight)
词根记忆：van(空)+ish--消失
例：Of the five hundred million different species of living creatures that have appeared on Earth, nearly 99 percent have vanished.
同根词：vanity(n．空虚；虚荣)
3.variable n．可变物(something that is variable)；变量，变数(a quantity that may assume any one of a set of values)
词根记忆：vari(变化)+able--可变的--变量
例：The key variables driving costs are size and type of order.
同根词：variation(变动)：varied(各式各样的)
4.variation n．变化：变异（the act or process of varying）
词根记忆：vari(改变)+ation(状态)--变化
例：There is a considerable degree of variation in shade of color between weeds of different species.
同根词：variable(a.易变的;n．变量)
5.varsity n．大学(university)；大学代表队（尤指体育）(the principal squad representing a university, college, school, or club especially in a sport)
例：Their level of participation in extracurricular activities and varsity sports is unusually high.
6.vegetarian n.素食者(one who believes in or practices vegetarianism);a．素食的(consisting wholly of vegetables fruits, grains, nuts, and sometimes eggs or dairy products)
词根记忆：veget(植物)+arian--只吃植物的人--素食者
例：Vegetarians refer to those whose diet consists of plant products only.//The diet of the ordinary Greek in classical times was largely vegetarian.
7.vegetation n．植被(plant life or total plant cover( as of an area))
词根记忆：veget(植物)+ation--植物的集合--植被
例：The relationship between vegetation and climate is not direct.
同根词：vegetarian(n．素食者)
8.vegetative a.植物的，有关植物生长的(relating to, composed of，or suggesting vegetation)
例：A plant's fecundity is high if it can reproduce quickly by means of vegetative growth.
9.vein n.纹理(texture)；矿脉(a regularly shaped and lengthy occurrence of an ore);静脉(a blood vessel that carries blood from the capillaries toward the heart)
例：A gold-quartz vein system originates in magmatic fluids.