Plan: 1 Coordinating conjunctions

Yet is sometimes combined with other conjunctions, but or and. It would not be unusual to see and yet in sentences like the ones above. This usage is acceptable.
The word FOR is most often used as a preposition, of course, but it does serve, on rare occasions, as a coordinating conjunction. Some people regard the conjunction for as rather highfalutin and literary, and it does tend to add a bit of weightiness to the text. Beginning a sentence with the conjunction "for" is probably not a good idea, except when you're singing "For he's a jolly good fellow. "For" has serious sequential implications and in its use the order of thoughts is more important than it is, say, with because or since. Its function is to introduce the reason for the preceding clause:

• 
  John thought he had a good chance to get the job, for his father was on the company's board of trustees.
  
• 
  Most of the visitors were happy just sitting around in the shade, for it had been a long, dusty journey on the train.
  

Be careful of the conjunction SO. Sometimes it can connect two independent clauses along with a comma, but sometimes it can't. For instance, in this sentence,

• 
  Soto is not the only Olympic athlete in his family, so are his brother, sister, and his Uncle Chet.
  

where the word so means "as well" or "in addition," most careful writers would use a semicolon between the two independent clauses. In the following sentence, where so is acting like a minor-league "therefore," the conjunction and the comma are adequate to the task:

• 
  Soto has always been nervous in large gatherings, so it is no surprise that he avoids crowds of his adoring fans.
  

Sometimes, at the beginning of a sentence, so will act as a kind of summing up device or transition, and when it does, it is often set off from the rest of the sentence with a comma:

• 
  So, the sheriff peremptorily removed the child from the custody of his parents.