I.根据本单元所学单词及所给的提示，写出所缺单词的正确形式。
1. In order to survive, human beings need to ________ (消耗) food and water.
2. The information is processed in a(n) ________ (任意的) order.
3. Early warnings of rising water levels prevented another major ________ (大灾难).
4. Johnson ________ (陈述) that he knew nothing about the case.
