my car had a trail of liquid and a spot ,could it be the sir conditioner? water?

I would not be worried. If it isn't oily then it cannot be engine oil, power steering fluid, transmission fluid, brake fluid, etc... the other option is coolant, but you would have mentioned the color or the sweet smell. I'm thinking water from the air conditioner. The air conditioner acts as a dehumidifier for the cabin of the vehicle, and water that is pulled from the air is drained from a one-way valve onto the pavement.