Complete the sentence with the correct form of the verb in brackets: "After years of practice, she ____ (become) a confident public speaker in 2021."

Explication

A finished change at a stated past time (in 2021) needs the past simple. Become is irregular, and its past simple is became — the only one of its three forms that differs from the base. Leaving the verb as become would leave the sentence with no past tense at all.