41. English about as a preposition meaning of is translated de; meaning in regard to or concerning it is rendered acerca de; meaning almost, nearly, in the neighborhood of it is cerca de or más o menos.
What are you talking about?
¿De qué habla usted?
I have to write to him about that matter.
Tengo que escribirle acerca de ese asunto.
I have about a hundred.
Tengo cerca de ciento (ciento más o menos).
42. To be about to is rendered estar al punto de or estar para.
When we arrived, the others were about to leave.