If you want to say that what happens would not be affected by either of two opposite situations, you use a clause beginning with whether or not.
Whether or not people have religious faith, they can believe in the power of love.
I get an electrician to check all my electrical appliances every autumn, whether or not they are giving trouble.
Or not can be put at the end of the clause.
Whether I agreed or not, the search would take place.
8.41
Always report such behaviour to the nearest person in authority, whether it be a school teacher or a policeman, or anyone else.
When the verb in a whether-clause is be and the subject is a personal pronoun such as they or it, you can omit be and the pronoun. For example, instead of saying All the villagers, whether they are young or old, help with the harvest, you can say All the villagers, whether young or old, help with the harvest.
A fresh pepper, whether red or green, lasts about three weeks.
They help people, whether tourists or students, to learn more of our past.
8.42 When you want to say that something is the case and that it does not matter which person, place, cause, method, or thing is involved, you use whoever, wherever, however, whatever, or whichever.
Whoever wins this civil war, there will be little rejoicing at the victory.
Wherever it is, you aren’t going.
However it began, the battle would always develop into a large-scale conflict.
Whatever and whichever are used either as determiners or pronouns.
Whatever car you drive, keep fixing it and keep it forever.
The deficit is extremely important this year, whatever they say.
Whichever way you do it, it’s hard work.
Whichever you decide, I’m sure it will be just fine.
Another way of saying that it does not matter who or what is involved is to use no matter followed by who, where, how, what, or which.
Most people, no matter who they are, seem to have at least one.
Our aim is to recruit the best person for the job, no matter where they are from.
No matter how I’m playing, I always get that special feeling.
Purpose clauses: He did it in order to make her happy
8.43 When you want to talk about the purpose of an action, you use a purpose clause.
Here is a list of the most common conjunctions used in purpose clauses:
in order that
in order to
so
so as to
so that
to
types of purpose clause
8.44 There are two kinds of purpose clause.
Clauses containing a to-infinitive are the most common.
They had to take some of his land in order to extend the churchyard.
Farmers have put up barricades to prevent people moving on to their land.
The subject of this type of purpose clause is always the same as the subject of the main clause.
This type of purpose clause is explained in paragraphs 8.45 to 8.46.
Other purpose clauses usually contain that.
Be as clear and factual as possible in order that there may be no misunderstanding.
This type of purpose clause is explained in paragraphs 8.47 to 8.48.
to-infinitive clauses
8.45 To-infinitive purpose clauses usually begin with in order to or so as to.
They were pushing in order to get to the front.
We had to borrow money in order to buy the house.
We fixed up a screen so as to let in the fresh air and keep out the flies.
If you want to make one of these clauses negative, you put not in front of the to.
Rose trod with care in order not to spread the dirt.
When removing a stain, work from the edge inwards so as not to enlarge the area affected.
8.46 Some purpose clauses can simply be to-infinitive clauses.
People would stroll down the path to admire the garden.
The children sleep together to keep warm.
To understand what is happening now, we need to think about what has been achieved.
However, you cannot use a negative with one of these structures. You cannot say, for example, We keep the window shut not to let the flies in. You would have to say, We keep the window shut in order not to let the flies in.
that-clauses
8.47 Other purpose clauses usually begin with in order that, so that, or so. They usually contain a modal.
If the verb in the main clause is in the present or in the present perfect, you usually use one of the modals can, may, will, or shall in the purpose clause.
…people who are learning English in order that they can study a particular subject.
If the verb in the main clause is in the past, you usually use could, might, should, or would in the purpose clause.
A stranger had lifted Philip up on his shoulder so that he could see better.
I bought six cows so that we would have some milk to sell.
She wanted the meal ready at six so she could go out at eight.
Ordinary verbs are occasionally used instead of modals, especially in negative purpose clauses.