to work overtime that evening, I missed a wonderful film.

A．Having been asked

B．To ask

C．Having asked

D．To be asked

三羧酸循环中发生底物水平磷酸化的反应是

A．枸橼酸→异枸橼酸
B．异枸橼酸→α→酮戊二酸
C．α→酮戊二酸→琥珀酰辅酶A
D．琥珀酰辅酶A→琥珀酸