Ability

I never remember password. (hopeless at)

I am hopeless at remembering password.

My parents don’t have a clue how to get broadband. (no idea)

My parents have no idea how to get broadband.

I was able to send an email, but I don’t know if it arrived. (manage)

I managed to send an email, but I don’t know if it arrived.

I could get emails, but I couldn’t send any. (be able to, not be able to).

I was able to get emails, but I wasn’t able to send any.