can is modal auxiliary verb. In the above sentence it expresses ability. Can can also express possibility and permission.
The word jump is a verb. The past tense is jumped. Jump can also be used as a noun (a jump).
Why is the beginning of a interrogative sentence.
In the sentence, "Which is his sister?", "which" is an interrogative pronoun.
Noun--however, many words have several possible parts of speech; please submit the Whole Sentence when asking for part of speech--cannot be sure without seeing how it is used in the sentence, as that's what determines the part of speech.
Her is a pronoun.
Jump is a verb. It describes an action.
"When" is an adverb when it begins a sentence.
verb (phrase)
it depends what word it is it could be any part of speech depending on the sentence
In a sentence, the word "action" can function as a noun.
The word jump is a verb. The past tense is jumped. Jump can also be used as a noun (a jump).
Turned is a verb in that sentence.
All subjects are part of speech for they are all nouns.
you
a sentence is a part of speech
Pronoun
Noun