Punctuation

Something as simple as a misplaced or missing comma can affect the clarity of a sentence. The following diagram illustrates the pattern for punctuation.


 
Some Pointers
  1. Always place a comma between two complete sentences joined by a coordinating conjunction (and, but, yet, so, and yet).

  2. Always place a comma after introductory prepositional phrases.

Start Exercise

Because a comma is missing in the following sentence, some readers will assume the italicized portion is one idea, will reach a point in the sentence (generally the verb) where they realize that something is wrong, and will then be forced to reread the sentence.


Hint
1. Original:

A precision full-wave rectifier is constructed using precision diodes and a square-wave generator is assembled using a schmitt trigger.

1.Hinted:

A precision full-wave rectifier is constructed using precision diodes and a square-wave generator is assembled using a schmitt trigger.

1. Revised:

Explanation

In the above example, the conjunction and separates two sentences. But without a comma before and, readers may assume that precision diodes and a square-wave generator are coordinated (i.e., joined by the and). Whenever you join two complete sentences with a coordinating conjunction (and, but, or, nor, yet, for, or so), place a comma before the conjunction to signal where one sentence ends and the next begins.


The following example demonstrates another punctuation problem that affects clarity by encouraging readers to misinterpret the grammatical relationships between words.


Hint
2. Original:

By participating more in scheduling release dates can be planned so that projects dovetail.

2. Hinted:

By participating more in scheduling release dates can be planned so that projects dovetail.

2. Revised:

Explanation

In this case, a comma is needed to signal the end of an introductory phrase and to clarify that the subject of the sentence is release dates. Because writers rarely recognize clarity problems of this sort while writing or revising their work, you should make a habit of placing a comma at the end of an introductory phrase.