A:x29−y227=1
B:x236−y2108=1
C:x2108−y236=1
D:x227−y29=1
由北京直达香港的铁路是( )
人体内氧气与血红蛋白分离的场所是( )
下列句子中没有语病的一项是( )
His teacher isn't happy his explanation.