How to Use "doubtful" with Example Sentences

1. Whether the government seizes the moment is altogether more doubtful .
2. Perhaps , but it is doubtful he would have succeeded .
3. Fourth , expect foreign affairs departments to stay in sight of doubtful regimes .
4. Police said he died after playing hide-and-seek with inmates , but this conclusion seemed doubtful .
5. The fish is also safe , although consumers are doubtful .