If one side fails to observe the contract,the other side is entitled to cancel it.
如果一方不履行合同协议,另一方则有权终止合同。
My dear friend, Mathilde. Let me tell you something. That necklace you borrowed from me wasn't a real diamond necklace. It wasn't valuable at all. The stones in the necklace were made of glass. It was worth five hundred francs at the most.