Ya que está aquí que vea lo que tiene que hacer.
—BENAVENTE.
Didn't I tell you? Do you think she is happy?
¿No te lo decía yo? ¿Crees que sea feliz?—JOSÉ DE LARRA.
(a) In the sense of to be enough, to do is rendered bastar. Meaning to serve as, be good for, it is translated servir (de).
That will do. You have taken too much time already.
Basta. Ya ha ocupado usted demasiado tiempo.
I have no letter paper. Will this postcard do?
No tengo papel de cartas. ¿Servirá esta tarjeta postal?
If it rains, this newspaper will do for an umbrella.