I can't keep up with you. ✬

You walk too fast for me to keep up with you. ✬

We must keep up with the times. ✬

Don't walk so fast. I can't keep up with you. ✬

I can't keep up with you if you walk so fast. ✬

I want you to keep up with me. ✬

I couldn't run fast enough to keep up with them. ✬

Keep up with the times. ✬

Keep up your courage. ✬

I have to study hard to keep up with the other students. ✬