English is a sentence-oriented language, “sentence” forms a unit. A verb is a necessary component of a simple sentence in standard English. Each verb defines the semantics roles of the argument in the sentence. Copula “be” here takes the proposition “very beautiful”, presenting a temporary state. The copula verb also changes its forms according to the number/person/tense aspect to show its morphological properties.
(It is noted that some dialects in the US accept questions like "where you at?". )
Apart from copula "be", English learners might also be puzzled about the use of do-support. NICE properties can help us differentiate whether a dummy auxiliary do/ do-support is needed. NICE refers to negation, inversion, code and emphasis.
Negation: She is not a teacher. (*She does not a teacher.)
Inversion: Is she a teacher? (*Does she a teacher?)
Code: She is a teacher, isn’t she? (*She is a teacher, isn’t she?)
Emphasis: She is a teacher. Yes, she IS. (*She is a teacher. Yes, she DOES.)
Similar to auxiliaries, the copula verb “be” also has the NICE properties. However, other linking verbs which take subject complement such as “become” require do-support in NICE constructions.
Negation: She did not become a teacher. (*She became not a teacher.)
Inversion: What did she become? (*What became she?)
Code: She became a doctor, and so did he. (*She became a doctor, and so became he.)
Emphasis: She became a teacher. Yes, she DID. (* She became a teacher. Yes, she BECAME.)
