Monday, December 05, 2005

suppose / supposed

1) I suppose I should go.
2) I am supposed to go.
3) He is the supposed leader.
The first difference between suppose and supposed is that suppose is a verb and supposed is an adjective. With this difference in mind, we can begin to understand the differences in meanings.

In 1), suppose has a meaning similar to think. Suppose generally expresses a belief that lacks certainty or an opinion.

In 2), supposed means required or obliged. It is similar in meaning to the modal should.
In 3), supposed means either mistakenly believed or based on not very strong evidence.

In 3), the meaning is closer to the verb meaning 1) than is 2).

Since 3) and 1) are somewhat similar, how can we tell them apart in reading?

Here are two sentences with supposed in them.
A. After waiting for a half an hour, she supposed her friend was not coming.
B. Her supposed friend had failed to support her in the disagreement.
In the first sentence, the verb, supposed, follows directly after the subject. In the second sentence, supposed is in the adjective place in a noun phrase, that is, it is in front of the noun.
The most common use of supposed, however, is after the BE verb as an adjective. In writing, don't forget the adjective form looks like the past tense, but it isn't really a verb, so it doesn't agree with time of the other verbs.

Suppose is sometimes used at the beginning of a sentence in an imperative sentence.
Suppose your parents don't come.
This sentence is used as a hypothetical statement, a sort of if-clause. It is similar to:
What if your parents don't come?
This use of suppose occurs when a writer wants the reader to think of something in a way that is different from the current reality.