一定的的英文：
certain
constant
determinate
stated
this
unvarying

参考例句：

The new show is certainly pulling in the crowds.
新的表演一定很吸引人。

Make sure the top is screwed back tightly onto the jar.
一定要把罐子盖拧紧。

I'll help you insofar as I can.
我一定尽力帮助你。

The party on Saturday night is going to be awesome. Booyah!
周六晚上的聚会一定很棒，哦耶！

You must copy it fair.
你一定要把它抄写清楚。

To wander from a set course or point of attention; stray.
离开一定的路线或注意点;游离

Take his vital signs at regular intervals.
每隔一定时间检查他的生命体征。

A lady who is house-proud must also like to keep open house.
一个讲究家里摆设的女人也一定很好客。

The effective permeability is stated as some numerical value at some given saturate conditions.
有效渗透率用在一定饱和条件下的数值表示。

He must have hit the jackpot with the sales of his last gramophone record.
他卖掉最后的一张留声机唱片，一定赚了大钱。

certain是什么意思：
adj. 确定，确实，某事，轻微的，微小的
pron. 某些

Certain kinds of wine go with certain kinds of food.
某些酒与某些饭食相配。

To forbid trading in certain goods or with certain supplier
禁止做生意，禁止做某些商品的交易或禁止与某些供应商做买卖

Certain estates are labelled as undesirable.
某些物业被归入不受欢迎之列。

constant是什么意思：
adj. 固定的；不停的，接连不断的
n. 常数；不变的事物

Matter is in constant motion and constant change.
物质总是在不断运动，不断变化的。

A constant guest is never welcome
常客令人厌

The market is in a constant state of flux.
市场行情在不断变化。

determinate是什么意思：
a. 确定的,一定的,决定的

He was determined to helm the exhibition.
他决定负责此次展览会的领导工作。

She is determined to make it to the top.
她决心要出人头地。

My father was a man of determination.
我父亲是一个果断的人。