Answer:
A finite verb is the word: knew
Noninfinite is the word: begin
Step-by-step explanation:
Finite verbs and nonfinite verbs differ in that the former can act as the root of an independent clause or a full sentence, whereas the latter cannot.
Take the following sentence as an example: The dog runs to the park to get a ball. Because it agrees with the subject (dog) and marks the tense, "runs" is a finite verb (present tense). Because it does not agree with the subject or mark the tense, "get" is a nonfinite verb.