题目

See the flag on top of the building ? That was ___ we did this morning .  A when                B. which          C. where                  D. what 答案：D 解析: D表语从句中缺did的宾语。A、B、C、D都是含碳、氢、氧的单官能团化合物。A水解得B和C，B氧化可以得到C或D，D氧化也得到C。若M(X)表示X的摩尔质量，则下式中正确的是 (    ) A.M(A)=M(B)+M(C)                                B.2M(D)=M(B)+M(C)C.M(B)＜M(D)＜M(C)                              D.M(D)＜M(B)＜M(C)