I know I didn’t forget ________ my camera with me because I clearly remember ________ it in my bag.

A．taking; to put

B．to take; to put

C．to have taken; putting

D．to take; putting

肝性脑病的假性神经递质学说中假性神经递质指的是__________，_________。他们是由食物中的________氨基酸如_________，_______合成的。其化学结构与正常的神经递质___________相似。