Sorry but you don't stand a chance if your lecturer said that.
Your lecturer obviously doesn't understand that the output impedance is too high so the voltage will drop to a mV level as soon as a 4R speaker is connected.
If your lecturer does not know this, then what chance do you have of learning anything?#
You might as well drop the course and work at Maplins (or a similar store in your area), you'll probably learn more about electronics there and you'll get paid for the privilege.