Carter was saying all the right things, but his smile was

Carter was saying all the right things, but his smile was_______, and I knew I couldn’t trust him.

preferential

artificial

official

beneficial

答案及解析：本题考查形容词辨析B选项，句意为“卡特说的都是对的，但是他的笑容很假，所以我不能相信他”。artificial “人造的，虚伪的”，综上，B选项正确。A选项，preferential “优先的，选择的，特惠的”，故排除。C选项，official “官方的，正式的”，故排除。D选项，beneficial “有益的”，故排除。故正确答案为 B项。