doubtful的例句是：用作形容词(adj.)It is doubtful whether it is true or not.这件事的真假是可疑的。doubtful的详尽释义是adj.(形容词)怀疑的，可疑的， 令人生疑的，不太相信的含糊的，疑惑的，有疑问的难以预测的不明确的不好的，未必好的低劣的未必货真价实的靠不住的，拿不准的。doubtful的读音是英['daʊtfl]；美['daʊtfl]。
一、详尽释义点此查看doubtful的详细内容
二、双解释义
三、英英释义
"the candidate's doubtful past"
"he has a dubious record indeed"
"what one found uncertain the other found dubious or downright false"
"it was more than dubitable whether the friend was as influential as she thought"
"they were doubtful that the cord would hold"
"it was doubtful whether she would be admitted"
"dubious about agreeing to go"
"drew a few tentative conclusions"
四、例句
It is doubtful whether it is true or not.
这件事的真假是可疑的。
The fact that he won the first place is doubtful.
他得了第一名是让人可疑的。
He is an author of doubtful reputation.
他是一位名声不太好的作家。
The ethics of his decision are doubtful.
他的这一决定是否合乎道德规范值得怀疑。
I am doubtful about the propriety of granting such a request.
我怀疑答应这项要求是否合适。
It is doubtful whether the old man will recover from the operation.
那老人手术后是否会康复难以确定。
五、词汇搭配
六、经典引文
A doubtful Passage in a Latin Poet.
出自：AddisonThe question whether certain doubtful forms should be ranked as species or varieties.
出自：C. DarwinIt was doubtful if he knew who Andrew Jackson was.
出自：Scott FitzgeraldA change which is not an unquestionable improvement is a doubtful blessing.
出自：E. F. Schumacher七、词语用法
doubtful的相关近义词
doubtful的相关反义词
doubtful的相关临近词
doubtless、doubt、doubtfully、doubtful of、doubtfulness、doubtful hit、doubtful loan、doubtful word、doubtful case、doubtful tale、doubtful debt、doubtful about