Answer: James, haz la tarea ahora mismo
Explanation: The verb "do" can be translated to the verb "hacer"
Do it means "haz esto" or "hazlo"
Do not do it means "no lo hagas" or "no hagas esto"
A singular command would be something like an order, for example:
"James, do the homework right now"
That can be translated to:
"James, haz la tarea ahora mismo"
Where the conjugation is for the verbal person "tu", like "tu haz.."
In some countries like Argentina or Uruguay, is more common to use the "vos"
In this case, the conjugation would be:
"james, hacé la tarea ahora mismo"