卤水豆腐是历史悠久的中国传统食品。卤水是制作卤水豆腐必需的稳定剂和凝固剂,其主要成分氯化镁是有毒的,但用卤水点制的豆腐不仅无毒,而且味道鲜美、营养丰富。这表明: ①事物的特性是不变的,其功能是不断变化的 ②事物的不同特性是由人的不同需要确定的 ③事物的特性是人们建立新联系的依据 ④事物在不同的联系中会有不同的特性
I wish I ___ able to tell him all about it last night.
The students ages ____ 15 to 18.
Only when your identity has been checked ____________.
The speech by the mayor of Shanghai before the final voting for EXPO 2010 is strongly impressed ___ my memory.
Having never met with such a _____ problem, he felt _____ and didn’t know how to solve it.