While

While is a subordinating conjunction. It usually introduces subordinating clauses of time. But sometimes while also expresses contrast.

Such…as

It wasn’t such a pleasant journey as we thought it would be.
She is not such a fool as you think her to be.

No sooner … than

Conjunctions which are always used in pairs are called correlative conjunctions. Note that most correlative conjunctions are of the coordinating type.

Examples are: either…or, neither…nor, not only…but also…, not…but, though…yet, both…and, so…that etc.

A subordinating conjunction joins a subordinate clause and a main (principal) clause. The subordinate clause can be a noun clause or an adverb clause. Note that a subordinating conjunction is not used to connect an adjective clause to another clause.

There are two main kinds of conjunctions:

Coordinating conjunctions
Subordinating conjunctions

Coordinating conjunctions join two clauses or sentences of equal rank. Here both clauses are capable of being principal clauses if they appear as such in separate sentences.

A conjunction is a word which merely joins two words, clauses or sentences. Note that a conjunction does not modify or qualify the words/clauses/sentences it joins.

The articles are not used:

1.    Before proper, material and abstract nouns used in a general sense:

London, France, Tom, gold, rice, honesty, virtue