Several words can be different parts of speech. For example and for instance can be prepositions or transitional adverbs. When they are used as transitional adverbs, they come at the beginning of the sentence and modify the entire sentence. Also pay careful attention to the fact that many transitional adverbs are also subordinating (dependent) conjunctions.
- To a great extent, a person’s habits decide his chances of getting cancer. For example, people who smoke are more likely to develop oral cancer.
In the example sentence given above, the expressions to a great extent and for example are transitional adverbs and can be removed without causing a grammatical error.
Now consider the sentence given below.
- People who smoke are likely to develop many diseases, for example cancer.
In the sentence given above, for example is used as a preposition and it connects its object (cancer) to the rest of the sentence.
Such as can only be a preposition. It cannot be a transitional adverb or conjunction.
- He plays many musical instruments, such as the guitar.
OR
- He plays many musical instruments, for example the guitar.
Because of and due to
Because of and due to are only used as prepositions. They cannot be used as transitional adverbs or conjunctions. In the same way, because cannot be used as a preposition or transitional adverb.
- Because of his long legs, he is a good basketball player. OR Due to his long legs, he is a good basketball player.
- He is a good basketball player because he has long legs.
Here because is a dependent conjunction that joins a subordinate clause to an independent clause to form a complete sentence.
The same idea can also be expressed using the transitional adverb therefore.
- He has long legs. Therefore, he is a good basketball player.
More examples are given below.
- She worked hard because she wanted to support her family. (Here the subordinating conjunction because joins the two clauses.)
- She worked hard because of her desire to support her family. (Here the preposition because of connects the phrase her desire to support her family to the rest of the sentence.)
- She wanted to support her family. Therefore, she worked hard. (Here we express the same idea using a transitional adverb.)