【题目】Our research has focused on a drug which is so powerful able to change brain chemistry.
A. as to be B. as not to be
C. as being D. as not being
在线课程【答案】A
【解析】考查固定句式。句意：我们的研究集中在一种药品上。这种药品如此有效，可以改变大脑的化学组成。so…as to do sth.是固定句式，意为“如此……以致于……”。故A选项正确。