Do not confuse doubtful, dubious, and suspicious. If you feel doubtful about something, you are unsure about it or about whether it will happen or be successful. Do you feel insecure and doubtful about your ability?... It was doubtful he would ever see her again. If you are dubious about something, you are not sure whether it is the right thing to do. Alison sounded very dubious... The men in charge were a bit dubious about taking women on. If you describe something as dubious, you think it is not completely honest, safe, or reliable. ...his dubious abilities as a teacher. If you are suspicious of a person, you do not trust them and think they might be involved in something dishonest or illegal. I am suspicious of his intentions... Miss Lenaut had grown suspicious. If you describe something as suspicious, it suggests behaviour that is dishonest, illegal, or dangerous. He listened for any suspicious sounds. ...in suspicious circumstances.

不要混淆 doubtful, dubious, suspicious。doubtful 指不确定某事或不确定其是否会发生或成功：Do you feel insecure and doubtful about your ability（你对自己的能力缺乏信心，抱有怀疑吗），It was doubtful he would ever see her again（他会不会再见到她还说不准）。dubious 指拿不准做某事是否正确：Alison sounded very dubious（艾利森听上去犹豫不决），The men in charge were a bit dubious about taking women on（几位男性负责人有点儿拿不准要不要招女员工）。dubious 还可指某事物不完全可信、安全或可靠：his dubious abilities as a teacher（他的教学能力令人怀疑）。suspicious 指不信任某人，怀疑其从事欺骗性或不法活动：I am suspicious of his intentions（我怀疑他动机不纯），Miss Lenaut had grown suspicious（莱诺小姐已经起了疑心）。suspicious 还可指某人的行为可疑、不诚实、涉及非法或具有危险性：He listened for any suspicious sounds（他注意倾听任何可疑的声音），in suspicious circumstances（在可疑的情势下）。