Uses of 'have' as an auxiliary verb

1 Have + past participle forms simple perfect tenses: e.g. / have He has eaten I had eaten [> 9.1-2]

2 Have + been + present participle forms perfect progressive: e.g. / have/I had been eating [> 9.2]

3 Have + been + past participle forms passives: e.g. It has been eaten [> I2.2n1] She must have been delayed [> 12.2n.2]

Questions/negatives with be and have as auxiliary verbs follow the same pattern as those for be as a full verb [> Chapter 13]. Have can function as an auxiliary and full verb in the same sentence [> 10.34-36],