Once in recovery mode I can't access developer Mode

I am working on a ASUS Chromebook Model REEF F2B-C4Q-N6O-V6G-K8D-Q6O. I have made it to recovery mode, but when I press ctrl+ b nothing happens. I know for sure those keys work, because I have been using the past couple days. This Chromebook did have an administrator at one time, but it has been power washed since then. Could that still be an issue? If not what else can I try?

‘ctrl+b’? try ctrl+d

sorry that was a mistype on my part. I meant that ctrl + d is not working.