doubtful

英 /ˈdaʊtfəl/ 　美 /ˈdaʊtfəl/

I was doubtful about buying a second-hand bicycle online.

我对在网上买二手自行车有些犹豫。

It is doubtful whether expanding roads alone can solve traffic congestion in rapidly growing cities.

仅靠拓宽道路能否解决快速发展城市的交通拥堵问题，尚存疑问。

搭配

doubtful about 对……不确定doubtful whether 是否……尚不确定of doubtful value 价值存疑的

人作主语常用 doubtful about；也可用 doubtful whether。

doubt (n.)、doubt (v.)、doubtfully (adv.)、doubtless (adv.)

近义 uncertain、unsure、questionable