Interrogativa: He will be able to wash the car for the weekend?
Negativa: He can not wash the car for the weekend.


Vamos lá, supondo que o tempo seja o Presente (Simple Present), a frase fica:

Aff: He washes his car on the weekends.

Int: Does he wash his car on the weekends?

P.s. Se você precisar em outro tempo verbal, só pedir :)