It's everyone's duty()giant pandasA.protectingB.to protectC.protectD.protected

问题描述:

It's everyone's duty()giant pandasA.protectingB.to protectC.protectD.protected

It's everyone's duty()giant pandas A.protecting B.to protect C.protect D.protected
选B.
原因:固定句型结构It+be+n +to do sth
其中,It 是形式主语,代替真主语 to do sth.原句可替换为:
【To to protect giant pandas主语】【 is 谓语】【our duty表语】.
习惯上,不定式、v-ing作主语,经常用形式It 代替.
句意:保护大熊猫是我们每个人的责任.