Since the mid-20th century,biology has truly come of age,achieving an importance equal to _____of ph

题目

Since the mid-20th century,biology has truly come of age,achieving an importance equal to _____of physics and chemistry.
C those Dthat
是将 physics and chemistry 看成整体么?何以见得
我很困惑 呵呵

答案

that,修饰的是importance （单数,不可数名词）.
physics and chemistry 看成整体.
自20世纪中叶始,和物理学,化学同等重要的生物学时代真正来到了.