Take another look at the sentence:

On Sunday Michael spent the afternoon waxing his new car. If he had knew about the two pop quizzes on Monday, he would have given his algebra problems and accounting spreadsheets more attention.

The second verb, had knew, is incorrect. This verb requires the past participle known because of the auxiliary verb had.

Know is an irregular verb; the chart below shows its forms.

Verb Simple Present Simple Past Past Participle
know know(s) knew known

Spent, the verb you chose, is perfectly correct. Before you continue, review the rules for irregular verbs.

Try again to become a champion!

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