生产者的行为目标是产量最大化原则。
参考答案:错
When ______ different cultures,we often pay attention only to the differences without noticing the many similarities.
A.compared
B.being compared
C.comparing
D.having compared
碳化塔中段气的进气位置应适宜,如位置过高,虽然结晶多,但是尾气中()会相应增大。
A、氨
B、二氧化碳
C、回卤
D、氧