Adverb clauses bring variety of information to sentences – time, place, manner, condition, concession, purpose, and more. Information on purpose, provided by adverb clause of purpose, is the topic of this post.
Learn more: This post covers just one adverb clause. Learn other types of adverb clause.
What is adverb clause of purpose?
Adverb clauses of purpose express purpose of the action being taken in the matrix clause. (Matrix clause is what’s left after removing subordinate clause. In the sentence They installed a security system so that their home would be protected against intruders, for example, They installed a security system is matrix clause.) They’re introduced mainly by subordinating conjunctions so that and in order that (in formal use), and occasionally by so (in informal use). Examples:
They installed a security system so that their home would be protected against intruders.
[The adverb clause shows the purpose of installing a security camera. Purpose is mentioned in the adverb clause; action taken is mentioned in the matrix clause.]
He turned off his phone so that he could focus on studying without any distractions.
The team worked late into the night in order that they might finish the project before the deadline.
He studied various languages in order that he could travel the world and communicate with locals.
If you noticed, all four contain a modal auxiliary (would, could, might, and could, respectively). That’s a requirement for adverb clause of purpose.
So far, we’ve looked at adverb clauses expressing predominantly one meaning: purpose. But adverb clauses are known for expressing multiple meanings simultaneously. Next up is such mix of meanings, one of which is purpose.
Mixed signals: An adverb clause may convey multiple meanings simultaneously
Adverb clauses introduced by if containing semi-auxiliaries be to or be going to can express meaning of condition and meaning of purpose, at the same time. Examples:
If you are to finish on the podium, you need a coach.
[Forget the subordinating conjunction if, which usually introduces adverb clause of condition, and just focus on the meaning conveyed by the underlined clause. You’ll realize that it conveys meaning of purpose To finish on the podium…]
If they are going to win the match, they need to score in the next few minutes.
Though the above clauses can be called adverb clause of condition or adverb clause of purpose, grammatically they’re both clauses rolled into one.
What is adverb clause of negative purpose (or prevention)?
So far, we’ve looked at only positive purpose, but sometimes you want to purposefully avoid something, leading to a negative purpose. Negative purpose can be expressed by in order that…not, for fear (that) [in formal use], in case, or lest [in formal use]. Examples:
Note: (that) means that is optional. For example, you can write either for fear or for fear that.
They set an early alarm in order that they would not oversleep before the flight.
She locked the door for fear (that) someone might break in while she was away.
They kept the receipt in case they needed to return the item to the store.
The team kept a first aid kit on hand in case of any injuries during the game. [Incorrect. In case of is a preposition, implying it’s a prepositional phrase – and not a clause.]
They arrived early at the airport lest they miss their flight due to long security lines.
The clause can be non-finite as well
We typically associate adverb clauses with what we’ve seen so far, the ones with subject and finite verb. (Grammatically speaking, these are finite adverb clauses.) But adverb clauses can be non-finite as well.
(Finite vs. non-finite clause: If you don’t know what finite and non-finite clauses are, here is a simplified difference between the two. A finite clause contains a finite verb. It’s another term for noun clause, relative clause, and adverb clause. A non-finite clause contains a non-finite verb. It’s another term for infinitive phrase, participial phrase, and gerund phrase.)
Non-finite clauses of purpose are infinitive phrases introduced mainly by to, in order to (in formal use), and so as to. Adverb clauses of purpose in fact occur more commonly as non-finite clause than as finite clause. Examples:
They went to the park to have a picnic.
To get to the airport on time, I took the metro.
They saved money in order to buy a car.
She tiptoed out of the room so as to avoid waking up the baby.
Non-finite clauses too can express negative purpose through introduction by so as not to and in order not to. Examples:
They took a different route in order not to encounter traffic.
I climbed carefully so as not to accidentally set off loose boulders down.
