One of the most important temporal conjunctions is quando. Quando corresponds to the English conjunction when. Sometimes the difference between a temporal clause and a conditional clause is not obvious.
temporal clause: Quando faz muito calor, eles são lentos.*
When it is warm, they are slow.
conditional clause: Se ele quer passar o exame, ele tem que estudar.
If he wants to pass the exam, he has to study more.
We use when if there is no doubt that the event will happen or has happened, "When he comes I ask him", or to describe a rule, When he is ill, he stays in bed <=> Everytime he is ill, he stays in bed. We use if, if / when (!) it is not clear whether the event / action going to happen. If / when we say "If he comes, I will ask him", it is not even clear whether he will come or not.
If can never be substituted by everytime: If I have money, I buy a car. <=> ~ Everytime I have money, I buy a ar.
Se faz muito calor, eles são lentos.
If it is warm, they are slow.
In this case the subordinate clause describes a hypothetical situation. If on a certain day, the day of the Marathon for instance, it is warm, the runners will be slower.
Sometimes the difference can vanish completely.
1) Fico triste quando vejo você triste.
I am sad, if you are sad. I am sad, when you are sad.
2) Fico triste se vejo você triste.
The difference between these two sentences is very small, one even could say that there is none. The difference between a regular coincidence of two event and a singular hypothetical situation can be very small, as in this case. However in other cases there can be a big difference. .
The event / action described by the subordinate clause introduced with quando can be hypothetical or real. If the event happened in the past, it is obviously real and the indicative is used. In the case that the subordinate clause is introduced by quando and the event / action is going to happen in the future there is no doubt that the event / action is going to happen, but it is unclear when it is going to happen. We use the futuro do conjuntivo in this case, see 12.2.5. We have therefore four different situations. The action / event has occured in the past: indicativo. We have a regular coincidence of two actions / events: indicativo. We know when the action is going to happen in the future: indicativo. It is not questioned that the event / action is going to happen in the future, but it is unclear when: conjuntivo.
quando with indicativo
The event / actions happened in the past
Tudo começou quando ele fazia tarefas no jardim.
Everything begun when he did some garden works.
Regular coincidence between to events / actions
É sempre quando menos esperamos, que a vida nos surprende.
Everytime when we least expect it, life surprises us.
Der Eintritt der Handlung gilt dem Sprecher als sicher
Quando vem, pergunto-lhe.*
If he comes, I ask him.
The event will happen, but it is unclear when
Quando tu disseres, eu começo.
Whenever you say it, I will start.
Quando can be as well interrogative adverb. As an interrogative adverbe it can be specified by a preposition.
quando as an interrogative adverb
Quando chegarão as encomendas dos últimos clientes?
When we get the last orders?
Até quando iremos nos calar?
Until when he will remain silent?
cada vez que = every time
Cada vez que vou para aquelas zonas vejo o quanto somos privilegiados.
Every time I go there I see how privileged we are.
Cada vez can be an adverb as well. In this case it doesn't introduce a subordinate clause, but describes the circunstances.
cada vez as an adverb
Isto cada vez faz menos sentido.
This makes less and less sense.
All temporal conjunctions follow the same logic. Facts and regular coincidence requires the indicativo. Insecurity concerning the moment when something will happen the futuro do conjuntivo.
Não posso sair enquanto meu bebê estiver dormindo.*
I can't leave the house while my baby is sleeping.
Enquanto você vai à padaria, eu vou ao açougue.
While you go to the baker, I go to the butcher.
Enquanto alguns foram embora, outros vieram ocupar seus lugares.
When some left, other took their seats.
Enquanto diretora da empresa, essa decisão ficará sob minha responsabilidade.
While I am the director of the company, I am responsible for this decision.
* estiver, futuro do conjuntivo, 3rd person singular. This is an irregular verb. The infinitivo pessoal and the futuro do conjuntivo differs in form.
assim que as soon as
Seque a roupa lavada assim que terminada a lavagem.
Dry the clothes as soon as the washing is finished.
Irá receber um email assim que o produto for* enviado.
You will get an email, as soon as the product has been sent.
Assim que estiver* pronto, será certamente publicado.
As soon as it is finished, it will surely be published.
Saímos assim que parou de chover.
As soon as it has stopped raining, we go out.
Assim que anoiteceu, fomos para casa.
As soon as it was dark, we went home.
* futuro do conjuntivo of the verb estar. It should be noted that in strong opposite to Spanish the presente do conjuntivo is not used, when the action refers to future, see 12.5.1. Sometimes you can find the remark in grammar books that the presente do conjuntivo is possible in Portuguese as well in these circumstances, this is a concession to what happens in reality, but in general the futuro do conjuntivo is considered the better choice in these circumstances.
If the action happened in the past, we have a fact and the indicativo is used.
Vim assim que soube*.
I came as soon as I heard it.
* saber, to know has two very different meanings. In imperfeito it means to know, but in pretérito perfeito simples it means to get to know. (I have known him for many years, but only last year I got to know his wife as well.)
Assim can have as well the meaning it suggests when translated literally, so. However in this case it is an adverb, not a conjunction.
Foi assim que soube que tinhas mudado.
That's how I heard that you had moved.
desde que since / from the moment
Desde que saiu do governo, Aznar* comanda um centro de estudos ligado ao Partido Popular.
Since he left the government, Aznar leads a think tank affiliated to the partido popular.
Desde que soube que ias** chegar descobri coisas bonitas da vida.
Since I heard that you would come, I discovered a lot of nice things.
Você será aprovado, desde que se esforce*** mais.
You will be accepted from the moment you make an effort.
* Aznar: Former president of Spain
** The future from the perspective of the past can be expressed in two different ways. One possibility is to express it with the conditional, see 13. The other possibility is ir in imperfeito + infinitivo. Ias is the second person singular of the imperfeito do indicativo of the verb ir.
*** Take note of the presente do conjuntivo. Actually the futuro do conjuntivo would be possible as well, but in this case the motivation is questioned and not the moment when the action is going to happen in the future.
Logo in Portuguese is a very romantic word, you should like it. It means immediately, soon, later. In othere words it can mean as well never, because later is a very flexible term. If you ever make a contract in Brasil or Portugal and the moment the project should be finished has to be fixed, take logo and you wont have any problem in legal disputes.
The conjunction logo que however means as soon as. The logic is the same as in quando, assim que, desde que. If the event has already happened, the indicativo is to be used. If it not questioned that the event will happen and the moment it will happen is known or if we describe the regular coincidence of two actions, the indicativo is used as well. However if it is unclear when an event will happen, we use the futuro do conjuntivo.
Logo que as soon as
Logo que fiz isso, uma coisa muito estranha aconteceu.
As soon as I did it, something happened that surprised me.
Logo que tiver novidades lhe avisarei.
As soon as I have news, I will get you informed.
To the conjunction there is a corresponding preposition. If we want to contruct with a preposition, we have to construct with something that can have the same syntactical function as a noun, in other words a verbal noun and the only verbal noun we have in Portuguese is the infinitivo (pessoal).
Logo depues de ter descansado* alguns dias, decidi continuar a viagem.
After having taken a rest, I decided to continue my trip.
* ter descansado is an infinitivo composto.
Logo alone, without que, can be as well a consecutive conjunction, in other words, introduce a subordinate clause that describes the result of an event described in the main clause.
Não estudou, logo não passou na prova.
He didn't study and therefore he didn't passed the exam.