血红蛋白的特征是（ ）
A：容易与氧气结合，容易分离
B：容易与氧气结合，不易分离
C：不易与氧气结合，容易分离
D：不易与氧气结合，不易分离
--I think it's really necessary. It is reported that the food that Chinese people
every year is enough to feed 200 million people for a year.
①北京所在经线的地方时
②120°E的地方时
③东八区的地方时
④东八区的区时
