问题
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
答案：A
powerfu强有力的。在这里四个形容词中, 只有powerful (有效力的) 可与表示药物的名词搭配。influential 有影响的, 有势力的, monstrous 异常大的, vigorous 精力旺盛的,