1
be doubtful about/of sth
后接名词或动名词，表示对某事不确定或怀疑。
She was doubtful about his honesty.
她对他的诚实感到怀疑。
怀疑的；拿不准的
先理解核心含义，再看它在真实句子里的用法。
怀疑的；拿不准的
Feeling or showing doubt; uncertain in opinion.
She was doubtful about his honesty.
她对他的诚实感到怀疑。
不确定的,或引起怀疑的。
Subject to, or causing doubt.
可疑的,值得怀疑的
open to doubt or suspicion; ; ; ; - Karen Horney
感到或表现出怀疑的,持怀疑态度的。
Experiencing or showing doubt, skeptical.
充满不确定或怀疑的
fraught with uncertainty or doubt
I'm doubtful about his ability to finish the project on time.
我对他按时完成项目的能力表示怀疑。
AI contextual example
It is doubtful whether the meeting will be held today.
今天是否举行会议还不确定。
AI contextual example
The authenticity of the document is doubtful.
这份文件的真实性可疑。
AI contextual example
the candidate's doubtful past
这位候选人可疑的过去
WordNet
后接名词或动名词，表示对某事不确定或怀疑。
She was doubtful about his honesty.
她对他的诚实感到怀疑。
后接从句，表达对某事的怀疑。
I am doubtful that the plan will succeed.
我怀疑这个计划能否成功。
it作形式主语，后接whether或if引导的主语从句。
It is doubtful whether they can finish on time.
他们能否按时完成还不确定。
Not this
I doubtful that he will come.
Use this
I doubt that he will come.
错误：将形容词'doubtful'误用作动词。'doubtful'是形容词，不能直接接从句。应使用动词'doubt'来表达'怀疑'。
Not this
She is doubtful to the plan.
Use this
She is doubtful about the plan.
错误：介词搭配不当。'be doubtful'后应接'about'表示'对...感到怀疑'，而非'to'。
Focus on the distinctions below. Other candidates are kept compact until a reliable usage note is available.
对…怀疑的
She was doubtful about the plan's success.
她对这个计划的成功表示怀疑。
…是值得怀疑的
It is doubtful that he will arrive on time.
他能否准时到达值得怀疑。
怀疑的表情
He gave her a doubtful look.
他向她投去怀疑的目光。
可疑的质量
The product is of doubtful quality.
这个产品质量可疑。
仍然怀疑
Despite the evidence, he remained doubtful.
尽管有证据，他仍然怀疑。
看起来可疑
The weather looks doubtful for tomorrow's game.
明天的比赛天气看起来不确定。
可疑人物
He is a doubtful character, so we should be cautious.
他是一个可疑人物，所以我们应当小心。
可疑的名声
The company has a doubtful reputation in the industry.
这家公司在业内名声可疑。
不确定的结果
We are facing a doubtful outcome.
我们面临一个不确定的结果。
战局悬而未决，就像两个疲惫的游泳者互相纠缠，窒息了彼此的技术。
This line from Shakespeare's Macbeth uses 'doubtful' to describe a stalemate in battle.
此句出自莎士比亚《麦克白》，用'doubtful'形容战局的胶着状态。
Use doubtful naturally, then get feedback on meaning, tone, grammar, and phrasing.
Revisit a common error or keep this word in your review list.
想象心里装满怀疑（doubt）的状态，就是doubtful。
通常用于表达怀疑或不确定的状态，既可用于客观评价（如可疑事物），也可用于主观感受（如内心不确定）。语域偏中性，在日常对话和正式书面语中都常见。
常用于 be doubtful about 或后接 whether/if 从句表示怀疑；也可后接 that 从句。
Dictionary facts from DICTIONARY_API_DEV, ECDICT, WIKTIONARY.