液体的蒸气与空气组成的混合物与火源接近时，初次发生蓝色火焰闪光的温度称为该物质的闪点。凡是闭杯试验闪点等于或低于61℃的液体称之为易燃液体。
参考答案：对
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)
岩溶地貌根据形态特征分如何分类？
