改善 in English:

people are trying to improve their diets

I'd like to improve my English.

I'm going to improve my score, time me.

Try to improve your speaking skills.

I want to improve my English.

I have to improve my German.

I want to improve my drawing skills.

Doing mental exercise is a very good method to improve your memory.

to improve the offer

They've been trying to improve the children's diet.

They have to improve the image of the company.