男，35岁。有急性间隙性血卟啉病，因急性阑尾炎拟行手术治疗。

血卟啉病的原发性缺陷是下列哪些物质的缺乏（）

A.维生素B

B.维生素A和D

C.尿卟啉原合成酶

D.2，3-二磷酸甘油酸

E.卟吩胆色素原

In the preface （） my book, I express my sincere gratitude to all the teachers and friends who have been of help to me during my three years' life in the university.

A．on

B．for

C．to

D．in