could snow
Regular verb: snow - snowed- snowed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
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it could snow
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it could be snowing
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it could have snowed
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it could have been snowing
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Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
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it couldn't snow
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it couldn't be snowing
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it couldn't have snowed
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it couldn't have been snowing
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Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
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could it snow?
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could it be snowing?
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could it have snowed?
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could it have been snowing?
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Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
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couldn't it snow?
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couldn't it be snowing?
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couldn't it have snowed?
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couldn't it have been snowing?
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