Many popular children's books ____ ____ by Doctor Seuss in the 20th century.
当血液通过肺泡周围毛细血管时,氧含量发生变化,下列正确的表示该变化的曲线是( )
①H2→H2O; ②CO2→CO; ③CO→CaCO3; ④Fe3O4→Fe.
生活中一些物质的pH如下图所示,其中碱性最强的是( )