1. Infinitives Present Active Infinitive = 2nd prin. part
amo, AMA/RE, amavi, amatus, -a, -um
to love
(The action of the present infinitive happens at the same time as the action of the main verb)
Present Passive Infinitive – change final -e  -i
amare – to love  amari – to be loved
docēre – to teach  docēri – to be taught
3rd conj. changes the whole ending: ducere - to lead  duci - to be led
audire– to hear  audiri – to be heard

2. amo, amare, amavi, amatus-a-um
(Perfect – before the main verb)
Perfect Active Inf. = perf. stem (from 3rd prin. part) + esse amavisse / to have loved
Perfect Passive Inf. = perf. pass. part. + esse
amatus esse / to have been loved
(Future – after the main verb)(sum, esse, fui, futurus-a-um)
Future Active Inf. = participial stem + -urus + esse
amaturus esse / to be about to love

3. Indirect Statement A verb of mental action leads to acc. + inf.
{the acc. + inf. is the Indirect Statement}
spero Iacobum Dianam amare. I hope [that] Jack loves Diane.
acc. subj. of inf. acc. obj. of inf same time as main verb
speravi Iacobum Dianam amare. I hoped [that] Jack loved Diane.
acc. subj. of inf. acc. obj. of inf same time as main verb
scio Iacobum a Diana amari I know [that] Jack is loved by Diane.

4. puto Iacobum olim Annam amavisse. I think [that] Jack once loved Anna.
acc. subj. of inf acc. obj. of inf before the main verb
putavi eum Poppaeam amavisse I thought [that] he had loved Poppaea.
subj. of inf. obj. of inf before the main verb
scio eum ab Anna amatum esse I know [that] he was loved by Anna.
subj. of inf. abl. of agent before the main verb
putavi Dianam a Marco amatam esse. I thought [that] Diane had been loved by Mark.
subj. of inf. abl. of agent before the main verb

5. spero eum me amaturum esse
spero eum me amaturum esse. I hope [that] he is going to love me/will love me.
acc. subj. of inf after the main verb
scivi eam Iacobum amaturam esse. I knew [that] she was going to/would love Jack.
subj. of inf after the main verb