Hi Sonia, a) complete is an adjective Eg: Whole b) completed a past tense verb. Eg: Finished In saying that, colloquially it is 'normal' to use a) as a past tense verb too. People will generally understand what you mean, as the context of the situation will help.

The deal is complete. It has all the necessary parts to make it work. Here, complete is an adjective. The deal has been completed. It is finished/over. It is a verb in the past tense. It is normal English usage.