Certain is an adjective.
Scared can be used as a verb in certain ways, e.g. "you scared me" where it is in the past tense.But it can also be used as an adjective (scared tourists).
"No" is usually an interjection or an adjective, but never a verb!
Coincide is a verb. Coincidental is the adjective.
Surge is a noun (a surge) and a verb (to surge). It is not an adjective.
Verb
Certain is not a verb so it does not have a past tense.
A verb = Participle, which can turn into an adjective in certain contexts.
The direct object in the sentence "are you certain of that" is "that." It is the thing that the subject (you) is certain about.
No, it is a verb or a noun (to go around, to surround; a round shape). The adjective form is circular.
The word positive is an adjective. It means to be certain.
Adjective.
Yes, it is an adjective meaning having a certain texture. The noun form is crunch, and the verb crunch means to chew noisily.
peeked a adjective or verb
No, it is an adjective. Breathe is a verb, breathing is a verb too... but then breathable is an adjective, which makes unbreathable an adjective.
Scared can be used as a verb in certain ways, e.g. "you scared me" where it is in the past tense.But it can also be used as an adjective (scared tourists).
The word 'sometimes' is an adverb, a word used to modify a verb, an adjective, or another adverb as 'on certain occasions or in certain cases but not always'.Examples:We sometimes go to the beach in the summer.He is a sometimes brilliant student when he make the effort.
It's an adjective.