keep up

Short definition from Wiktionary

Verb

1. 1
   To maintain; to preserve; to prevent from deteriorating or falling.
2. 2
   To continue with (work, etc).
3. 3
   To stay even or ahead.
4. 4
   To ensure that one remains well-informed about something.
5. 5
   To prevent someone from going to bed or to sleep
6. 6
   To use capital letters as much as reasonable.