can happen
Verbo regolare: happen - happened- happened

Affermazione 	
Forma semplice 	Forma con V-ing 	Perfetto 	Perfetto con V-ing 	
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it can happen
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it can be happening
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it can have happened
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it can have been happening
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Negazione 	
Forma semplice 	Forma con V-ing 	Perfetto 	Perfetto con V-ing 	
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it can't happen
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it can't be happening
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it can't have happened
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it can't have been happening
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Forma interrogativa 	
Forma semplice 	Forma con V-ing 	Perfetto 	Perfetto con V-ing 	
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can it happen?
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can it be happening?
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can it have happened?
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can it have been happening?
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Forma interro-negativa 	
Forma semplice 	Forma con V-ing 	Perfetto 	Perfetto con V-ing 	
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can't it happen?
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can't it be happening?
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can't it have happened?
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can't it have been happening?
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