一定 in English:

The constant border wars between England and Scotland came to an end.

Despite Trang's constant affirmations of love, Spenser is still afraid someday she will fall out of love with him.

Female driver, constant danger.

Constant dripping wears away a stone.

Cole's Axiom: The sum of the intelligence on the planet is a constant; the population is growing.

Commoners had no stake or interest in the constant fighting between nobles.

We can say that Japan was fighting a constant battle against hunger during the war.

A random variable is definitely a constant if the variance is zero

If we eat on constant time, our organism will know, that it can use in total energy from food, because in nearly time it gets new portion ‘energy fuel’.

A constant raise in prices of food products has been observed in the recent months.

The ​fridge ​keeps ​food at a constant ​temperature.

constant shift

Justice is the constant and perpetual desire to give to each one that to which he is entitled. Jurisprudence is the knowledge of matters divine and human, and the comprehension of what is just and what is unjust.

In studying geography, you must make constant use of maps.