水产品体表色素为（）。
A.肌红蛋白
B.血红蛋白
C.类胡萝卜素
参考答案：C
Not until he had left his friend _______ how important friendship was for him.
A．did he realize
B．he realized
C．had he realized
D．he had realized
试述如何对银行流动性进行调节，调节过程中应主要考虑哪些因素？
