Words similar to doubtful

Example sentences for: doubtful

How can you use “doubtful” in a sentence? Here are some example sentences to help you improve your vocabulary:

That's doubtful.
The Articles of Confederation explicitly stated that revision required the consent of every state, but the Philadelphia conventioneers, doubtful they'd achieve unanimity, lowered the threshold to nine of 13 states--on no authority but their own say-so.
Raised on the cool medium of television, undergrads are skeptical about passionate ideas, doubtful of genius, and intellectually timid.
Equally doubtful.
Whether these frames do the same thing as frames of film is doubtful, but Hollywood has certainly not spent one dime to find out.