English verb conjugation MUST THUNDER
Regular verb: thunder - thundered - thundered
Affirmation
Simple form
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it must thunder
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V-ing form
--
it must be thundering
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Perfect
--
it must have thundered
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V-ing perfect
--
it must have been thundering
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Negation
Simple form
--
it mustn't thunder
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V-ing form
--
it mustn't be thundering
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Perfect
--
it mustn't have thundered
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V-ing perfect
--
it mustn't have been thundering
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Interrogative form
Simple form
--
must it thunder?
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V-ing form
--
must it be thundering?
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Perfect
--
must it have thundered?
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V-ing perfect
--
must it have been thundering?
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Interro-negative form
Simple form
--
mustn't it thunder?
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V-ing form
--
mustn't it be thundering?
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Perfect
--
mustn't it have thundered?
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V-ing perfect
--
mustn't it have been thundering?
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