Incongruity takes many forms, all of them resulting from illogical relationships between parts of a sentence. Common incongruities are inaccurate predication or comparison; careless shifting in person, number, tense, point of view, or construction; and mixed or inappropriate metaphor. Some examples:
1. An example of the wrath of God is when he destroys Sodom.
Incongruous predication. In this kind of sentence the verb to be works as an equal sign (=). An example does not equal a when clause.
Correction: God's destruction of Sodom displays His wrath.
2. I like a small college because I can get to know the professors better.
Incomplete comparison: better than what else, where else, or who or whom else?
3. My high school physics course was fortunately just as hard as college.
Incongruous comparison: a single course cannot be compared with college.
4. What I found most surprising in college was that you can have a conference with your professors any time you want one.
Shift in person: if you begin with I, stick with it.
Better:...that I can have a conference with my professors....
5. Although the government allows eighteen-year-olds to vote, they refuse to trust them with liquor.
Shift in number: a collective noun (such as government, class, nation, family, team, or committee) may be considered as either singular or plural, but it must be treated consistently.
6. The story of Huckleberry Finn centers around the river.
Incongruous metaphor. The center, whether of a circle or of a story, cannot be "around" anything else. "Centers upon" or "revolves around" are both more logical, although both are somewhat overused.
7. Both Jane Eyre and Macbeth differ in their degrees of unselfishness and their willingness to accept their fates.
Incongruous because of redundancy: if A differs from B, B naturally differs from A. Therefore, Both is redundant.
Better: Jane Eyre and Macbeth differ....