单项选择题 Some—such as liquid oxygen—are so cold that they embrittle many constructional materials and evaporate continuously if not refrigerated.

单项选择题 When Joe was left to live with those people, he found that they were so ______ of life that he couldn't stay with them.

单项选择题 When you make the sacrifice in marriage, the psychologists say, you're sacrificing not to each other but to ______ in a relationship.