您好!
例:1) I couldn’t catch up with you,sorry。一般说这句话都会比较委婉,+个sorry。
2) I quite could not follow you
I can't follow you in a way.
I could hardly follow you.
follow = catch up with you
I can't follow you
I'm a little couldn't keep up with you
这就是我有点跟不上你的翻译了
I can't quite catch up with you.