An integral part of these clauses are conjunctions of time, which are very commonly used in English. When we come across a conjunction of time followed by other sentence elements, we can be almost certain that we are dealing with a clause of time.
As the name suggests, these subordinate clauses express actions or events related to time. They describe when an action takes place and whether it has actually happened or is only conditional. Before we take a detailed look at these clauses, however, let us collect the conjunctions that belong to this category:
when, as, while, before, after, since, till, until, for, as soon as, as long as, whenever, no sooner…than, hardly…when
These are all conjunctions that can occur in complex sentences. Now let us look at some important rules:
- We do not use future tenses in clauses of time; we use present, past, or perfect forms instead.
- We use the simple present or present perfect even when the sentence refers to the future.
- The conjunctions do not necessarily introduce a subordinate clause; they can also occur in the main clause.
- The order of the subordinate clause and the main clause can be reversed.
- We can use past tenses in clauses of time.
Therefore, neither will nor be going to can normally be used in the time clause. There is no problem with the main clause, where a future form can be used.
When all forests are destroyed, Earth will die.
In Hungarian, too, we use the present tense to refer to the future, so the present tense here refers to a future event. However, if we look closely at the sentence, there is no future tense in the subordinate clause; the future form appears only in the main clause. Here, we have simply placed the subordinate clause first.
Let us make the situation more complicated by using the past tense as well:
An airplane was flying over the sky as I was driving home.
Here we have used two Past Progressive forms. Now let us combine the continuous past with the simple past:
A fly landed on my arm as I was driving home.
Past tenses can therefore be used freely in both the main clause and the subordinate clause.
Past Perfect sentences do not cause any particular problems either:
Before I arrived home, the burglar had already stolen my cash.
Here, the Past Perfect appears in the main clause, but let us move it into the subordinate clause:
After the burglar had run away, I arrived home.
After after, a subject is needed in this type of construction to indicate that someone had already completed an action before another event took place.
Now let us look at the conjunctions one by one.
WHEN
When differs from if in that when refers to an event that is expected or considered to be real, whereas if refers to a conditional event. When and if are related because their meanings can be similar in certain contexts. Both can refer to a specific situation at a particular point in time. We should also note that when refers to a particular point in time.
I will turn off the music when my grandfather goes to bed.
So far, we have used the Simple Present in the subordinate clause. However, when is a conjunction that can also be followed by the Present Perfect. In this case, when refers to an event that must be completed at some point in the future.
When I have finished the driving course, I will buy a car.
UNTIL
Until expresses the idea that an action begins and continues until another event begins. It can describe an event that starts in the present or near future and ends when another event takes place.
I am swimming until it starts raining.
Ann and Joe didn’t want to speak to each other until they had made friends again.
In the second sentence, we can see that the event in the subordinate clause happened earlier, and when it was completed, another event began. The sentence also tells us that Ann and Joe eventually made up.
AS
- As can connect two events that happen at the same time:
As I was playing video games, the pizza arrived.
- When it is used with a perfect form, the subordinate clause refers to a completed action:
As I have finished dinner, you can use the kitchen.
AS SOON AS
As soon as expresses the idea that an event will happen in the future immediately after another event has ended. It is important to note that this conjunction suggests that very little time passes between the two events.
I will pay you back as soon as I get my salary.
I will pay you back as soon as I have got my salary.
The difference between the two sentences is that the perfect form emphasizes the completion of the first event more clearly than the present form.
As long as indicates a period of time during which an event continues from a particular point until another point.
As long as you do what I say, I won’t fire you.
They were swimming together as long as it was light.
The time interval, as we can see from the two sentences, can refer to either the present or the past.
BEFORE
Before refers to an event that happens prior to another event at some point in time. In other words, the event introduced by before happens before the event in the main clause.
I will finish my homework before I go out.
I won’t go out before I have finished my homework.
In the first sentence, the idea of completion is less explicit, but the sentence is grammatically correct and perfectly understandable. In the second sentence, the completion of the action is expressed more precisely.
AFTER
After after, we have an event that takes place before another event at some point in time. In other words, after introduces an earlier event because another event follows it.
After you change your ticket, you can get on the bus.
After you have changed your ticket, you can get on the bus.
There is not much difference between the two sentences. The perfect form simply emphasizes that the first action has been completed before the second one takes place.
The remaining conjunctions are more closely associated with particular verb forms, so their use is somewhat more restricted than that of the conjunctions discussed above.
SINCE
Present Perfect / Present Perfect Progressive
FOR
Present Perfect / Present Perfect Progressive
WHENEVER
Simple Present
NO SOONER…THAN
Inversion
HARDLY…WHEN
Inversion
One small note: I corrected a few obvious English mistakes in the original while translating—for example, “had ran” → “had run”, “on my arms” → “on my arm”, and “as long as it got dark” → “as long as it was light.” This makes the translated material suitable for actual teaching rather than preserving errors from the Hungarian source.