In the sentence, "Earlier, I helped the principal." the verb is "helped."
there is no verb
tense
The principal part of the verb "dig" in sentence 4 would be "dug," which is the past tense form of the verb.
Thunder is a noun, not a verb. You do not say "it was thundering earlier" you say "there was thunder earlier".
The second principal part of a verb in the third conjugation will end in -Δre.
It depends on whether the teacher and the principal are two different individuals or a single individual (which happens in some schools where principal happens also to be an active teacher). If teacher and principal are two separate individuals, then the verb form would be 'are'. If it is the same person who is the teacher and the principal, then the verb should be 'is'. Hope that suffices.
one
The future present perfect progressive tense of principal verb consists of "will* have been + {present participle of the principal verb}"; the present perfect tense of a principal verb consists of "have** been + {present participle of the principal verb}"; and the past perfect progressive tense consists of "had been + {present participle of the principal verb}". These tense are only rarely used. ___________________________ *"Shall" is substituted for "will" if the subject is in the first person or to show emphasis if the subject is in second or third person. **"Has" is substituted for "have" if the subject is in the third person singular only.
verb Here shopping is an auxuliary verb to the principal verb went.
The principal parts of a verb are the forms of the verb that you need to know in order to derive all the verb's possible forms. For "sing" these are:present tense: singpast tense: sangpast participle: sung
Tense could be a word that rhymes with fence and is formed from the principal parts of a verb (tense, tensed, tensed).
"Helped" is a verb that indicates an action. It is the past tense form of the verb "help."