(amare, amavisse, amatur-us -a -um esse 
 amari, amat-us -a -um esse)

*as noun 
Errare humanum est. To err is human.
Noli peccare. Do not sin.
Vivere est laborare. To live is to work.

*as noun clause having a subject in accusative
Gaudeo te venire. I am glad you come.
Gavisus sum te venisse. I was glad you came.
Gaudebo te venturum esse. I would be glad to have you come.

*indirect speech
Audivi parentes meos aegrotare. I heard my parents ill.
Dixit se aegrotare. He said himself ill.
Hoc optimum (esse) videtur. This seems to be the best.
Parentes mei aegrotare dicuntur. They say my parents are sick.

(ama-ns -ntis 
 amatur-us -a -um 
 amat-us -a -um 
 amand-us -a -um)

*as adjective: 
Gaudens te gaudentem video. I, a happy person, see you a happy person. 
Pueri obedientes placent omnibus. Obedient children please everybody.
Oculi dolentes aegre vident. Painful eyes see with difficulty.
Oculis dolentibus aegre videmus. We see with difficulty with painful eyes.
Oculi clausi nihil vident. Closed eyes see nothing.
Oculis clausis te etiam cognosco. I recognise you with closed eyes.

*as noun:
Vendentes fraudant ementes. Vendors cheat buyers.
Ridentibus non facile credimus. We believe, not easily, ridiculing persons.

*as verb:
Vacans virtute virtuti vacare debes. You, lacking virtue, need spend time on virtue.
Vix pransus noli iam libris incumbere! Having just eaten do not lean upon books.

*as verbal adjective (participle proper):
Pueri poenam timentes plorabant. Boys, afraid of punishment, cried.
Homo pauperum miserens benignus est. The man, pitying the poor, is kind.
Non misereor mendici laborem timentis. I pity not the beggar who is afraid of work.
Mendico laborem timenti non adsum. I do not help the beggar who is afraid of work.
Te hoc dicente, omnes mirabantur. All are surprised by your saying that.

*as passive adjective - ought to be - (gerundive):
Pauperes iuvandi sunt. The poor should be helped.
Hic sunt vestes lavandae. Here are clothes ought to be washed.
Hic non est ludendum sed laborandum. Here is not for playing but for working.
Tibi scribendum est a me. It ought to be written to you by me.
Media ad virtutem colendam sunt constantia et patientia. The means to cultivate virtue are constancy and patience.
Vero dicendo displices. You displease [people] by saying the true thing.
Vobis puniendis etiam ego puniendus sum. I ought to be punished if you ought to be punished. 

(amand-i -o -um -o) 

*as noun
Nunc tempus ludendi est. Now is time of playing.
Manus laborando aptae sunt. Hands are fit for working.
Manus ad laborandum aptae sunt. Hands are appropriate to working.
Errando discimus. We learn by making mistakes. 

(amat-um -u) 
*as noun [intention, mode]
Multi veritatem auditum venerunt. Many came for listening truth.
Hostes legatos pacem petitum miserunt. Enemies sent delegates for requesting peace.
Hoc est facile dictu, difficile factu. This is easy to be said, difficult to be done.
Veritas non semper est jucunda auditu. Truth is not always pleasing to be heard.