Final answer:
The grammatically correct sentence is 'We can share a milkshake if you want.'
Step-by-step explanation:
The grammatically correct sentence is: We can share a milkshake if you want.
In this sentence, the subject 'We' is followed by the helping verb 'can' and the main verb 'share'. The verb 'share' is conjugated with the pronoun 'you' as 'want', which agrees with the subject.
The incorrect sentence 'We can share a milkshake if you wants' includes the incorrect form of the verb 'want', which should be 'wants' to agree with the singular pronoun 'you'.
Learn more about grammatically correct sentence