问题
单项选择题
Our research has focused on a drug which is so ______ as to be able to change brain chemistry.
A．powerful
B．influential
C．monstrous
D．vigorous
答案
参考答案：A
解析： powerful“强大的”；influential“有影响的”；monstrous“畸形的”；vigorous“精力旺盛的”。答案为A。