人体血红蛋白中含有Fe2+离子,如果误食亚硝酸盐,会使人中毒,因为亚硝酸盐会使Fe2+离子转变成Fe3+离子,生成高铁血红蛋白,而高铁血红蛋白与O2结合非常牢固,使氧气无法释放出来。服用维生素C可缓解亚硝酸盐的中毒,这说明维生素C具有
If you leave the club, you will not be_____back in .
What I need is_____ book that contains ______ABC of oil painting.
Jenny nearly missed the flight______ doing too much shopping.
The CDs are on sale! Buy one and you get ______ completely free.
I’m sure that your letter will get______ attention. They know you’re waiting for the reply.