English Grammar

Be as an auxiliary verb

With the Present Participles

Be is used with the present participles of verbs to make the present and past progressive tenses.

• I am writing. (Present Progressive)
  
• She was standing at the gate. (Past Progressive)
  
• She is knitting a sweater. (Present Progressive)
  
• You were sleeping. (Past progressive)
  

With the Past Participles of Transitive verbs

Be can combine with the past participles of transitive verbs to form the passive voice.

• I was shocked.
  
• He was treated badly.
  
• You are rewarded for your service.
  
• They are sold cheap.
  

With the past participles of Intransitive verbs

Be can combine with the past participles of certain intransitive verbs to form the perfect tense.

• He is gone. (= He has gone.)
  
• You are quite grown up. (=You have quite grown up.)