doubtful的意思是懷疑的。
doubtful的意思是懷疑的；可疑的；令人生疑的；疑心的；不能確定的。懷疑的英文是doubtful。
doubtful造句
1、I remain?doubtful?about this proposal.
我對這次的提案持懷疑態度。
2、The purpose of his coming to this party is still?doubtful.
他來這個派對的目的仍然令人懷疑。
3、It is?doubtful?whether this project can be carried out smoothly.
這個項目能否順利執行值得懷疑。
4、I was still very?doubtful?about the chances for success.
我對能否成功仍然深表懷疑
5、I'd love to go on the trip, but I'm?doubtful?about its feasibility.
我很想參與這次旅行，但是我對它的可行性表示懷疑。