单选题The tables and pictures&n

问题补充：

单选题Thetablesandpictureshelpmake________clear________Iwasn sureofbefore.A.it; for me to understand whatB.it; everythingC.everything; to understand whatD./; what

答案：

A解析it为形式宾语，后面的不定式作真正的宾语，what从句为宾语从句，what又在宾语从句中作of的宾语。