To step up something (or step something up) is to do more of an activity, work harder at it, or increase the level or strength of something in order to improve a situation.
Examples of use:
1. We’re going to sell out of Christmas puddings long before Christmas if we don’t step up production.
2. With the exam date getting closer the English teacher stepped up the pressure on her students to do their homework.
infinitive – step up
present simple – step up and steps up
-ing form – stepping up
past simple – stepped up
past participle – stepped up
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