Être is an irregular French verb meaning "to be". It ranks among the top 10 most-used French verbs. Used in compound tenses and passive voice constructions
Who, that, and which connect noun phrases to modifying clauses. Relative pronouns modify or describe noun phrases. Non-restrictive clauses require commas, restrictive clauses don't
Antecedent establishes meaning of pronouns and other pro-forms. Pro-forms can follow or precede their antecedents. Anaphora is closely related term for antecedent and pro-form
Auxiliary verbs are small set of verbs that modify other verbs' meaning. Term "auxiliary" originally applied to prefixes and prepositions. Modern grammars define auxiliary verbs based on grammatical properties
Who, whose, when, where, which are used to indicate relationships. These pronouns can be used with nouns to describe people, places, and time
Modifying clauses add information about nouns or noun phrases. Clauses can be reduced by omitting that, which, or who and the be verb. Reduced clauses can be adjective phrases, gerund clauses, or past participle clauses