用法:
1 state of beinglegally acceptable （法律上）有效; 合法（性）:
test the validityof a decision 验证某决定是否合法.

用法:
2 state of being logical 合逻辑; 正确（性）:
question the validity of an argument, assumption 对某一论据、 假定的论点的正确性提出疑问.

• to mind(to my mind)
• to no end(without end)
• to one's knowledge(to the best of one's knowledge)
• to one's purpose(to the purpose)
• to say nothing of(nothing to speak of)
• to taste(to one's taste)
• to the day(to this day)
• to the wall(up the wall)
• to(toward （ s ）)
• to(up to)
• too(all too, only too)
• town(a twon, the town)
• tread on sb's heels(tread on sb's toes)
• trend(tendency)
• triumphal(triumphant)
• trouble oneself(trouble one's head)
• true(truly)
• trust in(trust to)
• try doing sth(try to do sth)
• try to do sth(try and do sth)
• turn a hand(turn a hair)
• turn one's back on(turn one's back to)
• turn out(turn out to be)
• turn the scales(tip the scales, turn the tables)
• turn(turn out)