IN QUESTIONS AND WITH TIME EXPRESSIONS

                                  IN QUESTIONS

When a sentence in either the Present Simple or Past Simple tenses has to be as a main verb, then no auxiliary verb is needed for forming questions. The be verb form is inverted before the subject. In other words, the verbs to be and to do do not appear in one verb phrase together.

Positive sentence – She works in Madrid.

Yes/No question – Does she work in Madrid ?

[ to be is not he main verb, auxiliary verb needed]

Positive sentence – She is from Spain.

Wh question – Where is she from ?

[ to be is the main verb, no auxiliary verb needed]

Positive sentence – She is my friend from Spain.

Wh Subject question – Who is she ?

[ to be is the main verb, no auxiliary verb needed in a Wh subject question]

                         WITH TIME EXPRESSIONS

Frequency adverbs appear after the verb to be and not before, as with other verbs.

She is usually on time and always works very well.

[ usually appears after is, always appears before works] 



LINKS:

https://www.really-learn-english.com/the-verb-to-be-forms-examples-grammar-exercises.html

https://sites.google.com/site/englishgrammarguide/Home/the-verb-to-be