Verbs
Perfect infinitive
Perfect infinitive = (to)
have + past participle
Perfect infinitives are used in the following
ways:
-with a modal verb, such as must, will,
would, can't, could,
might and may.
- The message should have arrived yesterday.
-after certain verbs and be + participle/adjective
(seem, look, appear,
hope, be known, be
thought, be said, be
happy, be pleased and be
sorry).
- A Queensland tiger is known to have existed.