The verb "to come" should be rendered in Spanish by ir when the person is not in the place in question at the time of speaking or writing, as—
¿Quiere V. venir aquí á mi casa mañana? Will you come here to my house to-morrow?
Hoy estoy indispuesto pero mañana iré á verle: To-day I am unwell (out of sorts), but to-morrow I shall come to see you.
La vi escribir: I saw her writing; viz., I saw her write.
La vi escribiendo: I saw her writing; viz., whilst she was writing.
The emphatic word in an English sentence is often and more elegantly translated by a paraphrase in Spanish—
¿Es verdad que ha comprado los géneros? Has he bought the goods?
¿Es él quien ha comprado los géneros? Has he bought the goods?
¿De veras ha comprado los géneros? Has he bought the goods?
¿Pues son los géneros lo que ha comprado? Has he bought the goods?