doesn't know how
No sabe cómo se lo agradezco, Doctora.
I can't thank you enough, Doctor.
— El secreto de sus ojos (2009)
Tom no sabe cómo expresar sus sentimientos.
Tom doesn't know how to express his feelings.
Tom no sabe cómo va a ir María al colegio mañana.
Tom doesn't know how María is going to get to school tomorrow.
El gobierno japonés no sabe cómo manejar el problema.
The Japanese government doesn’t know how to handle the problem.
Tom no sabe cómo pasó.
Tom doesn't know how it happened.
Está intentando silbar, pero no sabe cómo.
He's trying to whistle, but he doesn't know how.
El niño no sabe cómo comportarse.
The boy doesn’t know how to behave.
He/She doesn't know how to pick it up.
— Lagaan: Érase una vez en la India (2001)
O no sabe cómo lavar los platos o es que es muy vago.
Either he doesn't know how to wash the dishes, or he's just very lazy.