"You have to remember his name!"
Translation:¡Tienes que acordarte de su nombre!
When you use "acordar" to mean "remember" you must always add a couple things.
To make "acordar" into "remember" you first make it reflexive by adding "me", "te", "nos" or "se" depending on the subject who is doing the remembering.
Second, you must add "de" to connect that verb to the thing remembered.
"Recordar" is a lot simpler.
No reflexive, no connecting preposition.
I used "tienes que acordar' and went to the dictionary (actually google translate first) to find out why I didn't use it correctly.
It appears to me that acordar is only 'to remember' when used as a reflexive form. I will have another chance at this and will update it with my attempt at a reflexive verb structure (can you use a reflexive verb with 'tengo-que'?)
took me three more tries (typos and tense errors grrrr) Tienes que acordarte de su nombre was accepted. (NOTE to self: re-learn what I thought I knew about reflexive verbs)
• Beginner’s guide to Spanish reflexive verbs
Well technically recordar and acordarse de both mean to remember. But note the two differences.
same here with arcordarte de. Here is the exchange:
My rejected answer: tú tienes que acordarte de su nombre
Their "corrected" answer: ¡Tienes que acordarte de su nombre!
Other than punctuation and "tú" I see no difference.
I reported it. We will see where that goes.