Comparisons are a form of parallelism that require special attention. As the name indicates, comparisons are all about the comparison of two items that are usually located in two parts of the sentence. More than two items may also be compared, occasionally. The rule you need to remember is that parts of a comparison, much like items in a list (parallelism), must always have identical grammatical form and be logically similar to each other.
In order to understand how to approach comparisons questions, it is essential that you first understand how to spot the comparison(s), and identify the two parts of the sentence that are being compared to each other. Once the comparisons have been spotted, you have to ensure that the two parts of the sentence that carry the comparisons are parallel, both structurally and logically.
There are certain signal words or phrases that help you identify the comparisons. The most important comparison signals are “Like”, “Unlike”, “As”, and “Than”. Whenever you see one of these four words, stop and look for the two items being compared, and then check whether the comparison is expressed in parallel terms with regard to both grammar and meaning. To be grammatically and logically parallel, comparisons must be complete and unambiguous. Here’s an example to demonstrate this point:
Waking up early on a Sunday is significantly harder than Monday.
This sentence is both grammatically and logically incorrect because it attempts to compare “Waking up”, which is a gerund, with “Monday”, which is a noun. To maintain parallelism, you can compare either Sunday against Monday, or the act of waking up on either day. The correct sentence might thus read:
Waking up early on a Sunday is significantly harder than waking up on Monday.
Some other common comparison signals are “more than”, “as much as”, “as (adj.) as”, “less than”, “as little as”, “faster than”, “as fast as”, “different from”, “the same as”, and “in contrast to/with”.
Like vs. As
The two most common comparison signals “Like” and “As” are perhaps the most confused. In order to ace comparisons, you should learn to first distinguish between these two signals.
Like is a preposition. This means that “Like” can only be followed by nouns, pronouns, or noun phrases, but not whole clauses or (prepositional) phrases. Now, remember that a clause always contains a working verb that can be the main verb in a sentence. So, the basic fact here is that “like” cannot be used when comparing actions; it can only be used when comparing nouns.
Consider the following example:
Correct: Like her brother, Jona was good at basket-ball. OR Jona, like her brother, was good at basket-ball.
Here, like is followed by the noun phrase her brother (so we know that two nouns are being compared). The whole phrase “like her brother” indicates a comparison.
Note that like can be followed by gerunds (-ing forms used as nouns) as we saw in the previous example.
On the other hand, As can be either a preposition (appearing with a noun) or a conjunction (appearing with a clause). As is NOT the case with like, you can correctly use as to compare two clauses. So basically, to compare actions, you need to use the word “as”.
Incorrect: LIKE her brother did, Jona played basketball..
Right: Jona played basketball, as did her brother. OR Jona played basketball, as her brother did.
The words her brother did form a clause with the working verb “did”, making this a comparison of actions. Hence, you need to use as here to make the comparison between the two clauses Jona played basketball and her brother did. Using like to compare clauses is common in speech but always wrong in writing.
When you are under test conditions, it’s your choice whether you want to compare Jona and her brother directly, or what they did, but you must ensure that you use like or as appropriately.
Comparisons must be structurally parallel.
That is, they must have a similar grammatical structure.
Here’s an example:
Incorrect: I like to read books more than I enjoy listening to music.
As you can see, the objects of comparison here (i.e. books against music) are NOT grammatically parallel, because to read books does not have the same structure as listening to music. To read is an infinitive, whereas listening is a gerund (listening is being used as a noun).
To write a concise, parallel sentence, you should simply use one verb (like) and convert both objects to -ing forms.
Correct: I like reading more than listening to music.
Sometimes, in the second part of the comparison, words are omitted. This specifically happens in the case of possessive pronouns, as we can see in the following:
My car is bigger than Brian’s [car].
My car is bigger than the Smiths’ [car].
My toes are longer than Brian’s [foes].
My toes are longer than the Smiths’ [foes].
Even though the last word has been omitted from the sentences, each one of the above examples are grammatically correct.
Note that the possessing noun (Brian, the Smiths) can be singular or plural, regardless of whether the implied possessed noun (car, toes) is singular or plural. Any singular-plural combination is possible grammatically. You only need to make sure that the combination makes logical sense.
Omission is always a possibility, provided it leaves behind no ambiguity.
I walk faster than John (does)
She walks faster than me
The correct way of writing the latter sentence is:
She walks faster than I do.
- When comparing two things, you must use the Comparative Form (-er) of an adjective or adverb. When comparing more than two things, you should use the Superlative Form (-est) of an adjective or adverb.
- If you want to make a comparison for an adverb that ends with –ly, do not make the comparison by changing the ending to –er. Instead, add more.
Incorrect: Jennifer runs quickly. She runs quicker than Jacob.
Correct: Jennifer runs quickly. She runs more quickly than Jacob.
However, adverbs that do not end with –ly can be made into comparatives by adding –er.
E.g. Jennifer runs fast. She runs faster than Jacob.
- Always use than with a comparative form.
Wrong: I will have higher bills over last year.
Right: I will have higher bills than last year.