What is a counter-offer? What happens to the offer once a counte

What is a counter-offer? What happens to the offer once a counter-offer is made?
【正确答案】：If the offeren finds part of the offer unacceptable, he may raise his own proposals which constirute a counter-offer. A counter-offer may be made in relation to the price,terms of payment, time of shipment or other terms and conditions of the offer. Once a counter-offer is made, the offer will be invalid and unbinding.