题目

Ann, don't put your school things here. Please ________. A . put them away B . put away them C . put it away D . put away it 答案：A已知函数①；②；③；④．其中对于定义域内的任意一个自变量，都存在定义域内的唯一一个自变量，使得成立的函数是（    ）学 （A）①②④            （B）②③                  （C）③                  （D）④