[ yīdìng ] 1.(规定的, 确定的) fixed; established; regular 短语和例子 一定的规章制度 established rules and regulations; 一定的生产指标 fixed production quota; 按照一定的规格进行生产 work according to specifications; 学习、 工作都有一定的时间。 there are fixed times for study and for work.2.(固定不变的) definite; constant 短语和例子 每一种弹簧都有一定的弹性。 every sort of spring has a definite elasticity.3.(必定) surely; certainly; be bound to; necessarily 短语和例子 这一定是他想买的书。 this must be the book he wants to buy. 只要我们做到这一切, 改革就一定能成功。 provided we do all this, we shall assuredly succeed in our reform. 六点以前, 我一定回家。 i shall definitely be home before six o'clock.4.(特定的) certain; specific; given 短语和例子 在一定程度上 to a certain degree; 在一定条件下 under given conditions; 在一定意义上 in a certain sense; 在一定的时期内 within a certain [definite] period; 金属加热到一定的温度都会熔化。 metals will melt when heated to a certain temperature.5.(相当的) proper; fair; due 短语和例子 达到一定水平 reach a fairly high level; 给予一定的重视 attach due importance to