English has a set of words called conjunctions that enable us to gracefully transition from one part of a sentence to another part of the sentence. Some of the words in the set are inherently conjunctions and others are words that can function as conjunctions.

conjunction

I deem your grade to be a (C), and that is the grade I shall record.

This sentence has two complete sentences bundled into one sentence. Grammatically speaking, it has two independent clauses joined by a conjunction and a comma. The word and is the conjunction. The conjunction allows us to transition from the first independent clause to the second independent clause.

Rodriguez and Joan were my companions on the museum tour.

The conjunction in the sentence above allows us to use a compound subject, i.e., Rodriguez and Joan.

The leading financial burdens faced by most Americans at the beginning of the Twenty-first Century are housing, medical service, child care, and transportation.

The conjunction in the sentence above facilitates termination of a series. A series in English grammar is a list of things.

The mayor proposed a new regulatory ordinance, but the city council did not approve the measure.

The conjunction in the sentence above, but, means contrary. The conjunction facilitates the transition between independent clauses by conveying a sense that the meaning of the second clause is going to be different from the sense expressed in the first clause.

I am taking challenging academic courses, because I want to qualify for a good job.

The conjunction because means for this reason. The first independent clause is a statement. The conjunction provides a transition to the reason the statement was made.

I have an athletic scholarship, although I have a greater interest in computer science.

The conjunction although means regardless of that fact. The conjunction in the sentence above facilitates the transition from the thought expressed in the first independent clause to the different thought that follows.

Your privilege of participating in the athletic program will be terminated unless you improve your grade average.

The conjunction unless means except on the condition that or except under these circumstances. The speaker in the sentence above states that privilege will be terminated and then uses the conjunction to transition to the condition that will prevent termination of privilege.

We will be in the regional tournament if we win the game tonight.

The conjunction if means in the event that. In the sentence above the speaker makes a statement and then transitions to a qualifier. The qualification can also open the sentence as shown below.

If we win the game tonight, we will be in the regional tournament.

Your request must be approved by Mr. Valdez or by Mr. Palmer.

The conjunction, or, indicates that an alternative exists. In the sentence above the choice is Mr. Valdez or, alternatively, Mr. Palmer. The conjunction provides a transition from the first name to the alternative name.

Either Bonny or Clyde will be the next president of the Banker's Association.

The words either and or are paired in sentences to express an alternative condition.

Neither the airline companies nor the air terminals can prevent wind sheer.

The words neither and nor are paired to express a negative statement. The conjunction, nor, means not. Wind sheer cannot be prevented.

My car burns neither gasoline nor diesel fuel; it burns hydrogen.

words that function as conjunctions

No child will go hungry in this State while I am the Governor.

The word while can function as an adverb or as a conjunction. While means as long as or during the time that.

We will meet our humanitarian responsibilities during this financial crisis; however, some capital projects will be delayed.

The word however can function as an adverb or as a conjunction. However means nevertheless or yet.

Coping with the severe winter storms required 5000 manhours of overtime; consequently, our treasury is nearly empty.

The word consequently is an adverb that also functions as a conjunction. Consequently means as a result.

I have accepted a job at Silly Systems Software; therefore, I shall be leaving Programmers R Us at the end of the month.

The word therefore is an adverb that functions as a conjunction. Therefore means for that reason.

There are several other words that can function as conjunctions.