Active and Passive Voice

O sujeito pratica ou sofre a ação, isto é, o sujeito é agente ou paciente. 

Sujeito (agente) - voz ativa / Sujeito (paciente) - voz passiva.

Voz ativa (active voice), é utilizado ao falarmos uma sentença mais clara e direta.
Uma frase na voz ativa é composta por sujeito + verbo auxiliar + verbo principal + objeto.

Voz passiva (passive voice), é mais utilizado para textos formais. Damos mais ênfase ao objeto que está sofrendo a ação.

Verb Tense (tempos verbais)
Present Simple	am/are/is
Present continuous or Progressive	am/are/is + being
Present Perfect	have/has been
Past Simple	was/were
Past Progressive	was/were being
Past Perfect	had been
Future Simple	will be
Future  ''be going to''	am/are/is + going to be
Future Perfect	will have been

Active Voice	Passive voice + participle
Viviane drinks water.	The juice is drunk by her. The juice isn’t drunk by her.	Present Simple
Viviane is eating hot dog.	The hot dog is being eaten by Viviane. The hot dog isn’t being eaten by Viviane.	Present Continuous
Viviane made a cake	A cake was made by Viviane. A cake wasn’t made by Viviane.	Simple Past
He was driving a car.	The car was being driven by him. The car wasn’t being driven by him.	Past Continuous
I have seen the movie ten times.	The movie has been seen... The movie hasn’t been seen...	Present Perfect
She had eaten sushi.	Sushi had been eaten by her. Sushi hadn’t been eaten by her.	Past Perfect
Susana will buy a new bike tomorrow.	A new bike will be bought by Susana tomorrow. A new bike won’t be bought by Susana tomorrow.	Future Simple
They are going to open a shop.	A shop is going to be opened... A shop isn’t going to be opened...	Future ‘’be going to’’
You will have started the job.	The job will have been started by you.	Future Perfect

Modal Verbs	Active voice	Passive voice
I You He She It We You They	can drink water / can't drink water.	water can be drunk
	could drink water.	water could be drunk.
	might drink water.	water might be drunk.
	may drink water.	water may be drunk.
	must drink water / mustn't drink...	water must be drunk.
	ought to drink water.	water ought to be drunk.
	should drink water.	water should be drunk.
	will drink water.	water will be drunk.
	would drink water.	water would be drunk.

Com o uso da preposição.

They looked for the baby - active voice.

The baby was looked for - passive voice.

They listen to the music - active voice.

The music is listened to - passive voice.

Somebody sat on my purse - active voice.

My purse was sat on - passive voice.

Com sujeito indeterminado e o agente da passiva.

Somebody broke the window - active voice.
The window was broken - passive voice.
I climbed the mountain - active voice.
The mountain was climbed - passive voice.

Modal Verbs ou Modal Auxiliary Verbs.

Modal Verbs, são um tipo especial de verbos auxiliares que alteram ou completam o sentido do verbo principal.Em Inglês, para cada situação há um modal mais adequado.

Be able to	Ability.
Can	Ability / Suggestion / Request / Permission.
Can’t	Certainty that something is impossible / Probability (0%)
Could	Past ability / Polite / Permission / Possibility / Probability (30%)
Might (might not)	Possibility / Little Possibility / Probability (30% or less)
May (may not)	Possibility / Formal Request / Permission/Probability (50%)
Must	Obligation/Probability (100%)
Mustn’t (must + not)	Prohibition.
Have to	Obligation.
Don’t have to	Lack of Obligation. (falta de obrigação)
Need to	Obligation.
Needn’t (need + not)	Lack of Obligation. (falta de obrigação)
Ought to	Opinion / Advice.
Should	Opinion / Advice or Recommendation.
Will	Prediction / Spontaneous decision.
Would	Polite Request.

Exemplos:

1. You are able to play tennis very well.
2. I can speak English.
3. You've just had lunch. You can't be hungry.
4. She could go to the cinema.
5. Might I talk to you?
6. She might not work here any more.
7. He may be in his office.
8. It may not be true.
9. Louise must get very bored in her job. She does the same thing every day.
10. I have to work from 8.30 to 5.30 every day.
11. You need to study a lot.
12. Joe can stay here. He needn't come with us.
13. You mustn't tell lies.
14. You don't have to do it.
15. You should eat more fruit.
16. You ought to drive more carefully.
17. Oh, it's very cold in here. I will close the window.
18. Would you help me clean the house?