现在校园里常常有人爱说一些“生造词”或“流行语”。请把这些词语找出来，讨论：这样的词语是怎么形成的？使用这样的词语好不好？

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In relation to the formation of a contract in the context of the UN Convention for the International Sale of Goods, explain:

(b) the circumstances under which an offer may be terminated. (5 marks)