组成血红蛋白的珠蛋白肽链分为α和β两大类。每个血红蛋白分子由一条α肽链和两条β肽链连接而成，每条珠蛋白链含有一个亚铁血红素。
参考答案：错
—Come in Peter, I want to show something to you.
—Oh, how nice of you! I______ you ______to bring me a gift.
A．never think; are going
B．never thought; were going
C．don’t think; were going
D．hadn’t thought; were going
新项目的分类二类项目：在现有（）、环境和项目上扩展检定、校准、检验、检测能力的项目。
A.设备
B.标准
C.细则
D.评定
