🏃 動詞の形 ・ アオイ
TOEIC Part5文法問題 アオイ: Q4（動詞の形）
All visitors must ___ at the front desk before entering the building.
All visitors must ___ at the front desk before entering the building.
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正解: A) register
'Must' is a modal verb, and modals are always followed by the base form of the next verb. So 'register' is correct. 'Registers' is third-person singular present, 'registered' is past tense/past participle, and 'registration' is a noun — none of these can follow a modal directly.