To use a word family well, decide what job the gap does in the sentence, then pick the form that does that job. The meaning stays the same, and only the ending changes.
This lesson belongs to sentence building and paraphrase. It supports the paraphrase work in restating an idea without changing its strength, because a paraphrase often swaps a verb for a noun.
What forms can one word have?
Many words come in four forms. Here are three families.
| Verb | Noun | Adjective | Adverb |
|---|---|---|---|
| decide | decision | decisive | decisively |
| succeed | success | successful | successfully |
| prepare | preparation | prepared | (none common) |
Common endings give hints. -tion and -ment often make nouns.
-ful, -ive and -al often make adjectives. -ly often makes adverbs. These are hints, not rules, so check when you are unsure.
How do you choose the form?
Use the position test on the gap.
- After the, a, an, his, her and this: a noun, or an adjective followed by a noun.
- Between a determiner and a noun: an adjective.
- After a subject: a verb.
- Describing how something is done: an adverb.
- After is, are or was: an adjective or a noun, depending on what is being said.
Worked example
Complete the sentence with the correct form of the word in brackets:
The manager answered ______ (confident) and gave a ______ (decide) reply.
Step 1, first gap. It follows the verb answered and describes how she answered. That is an adverb: confidently.
Step 2, second gap. It sits between a and reply, so it must be an adjective. The family of decide gives decisive.
Step 3, read back. The manager answered confidently and gave a decisive reply. Both forms fit, and the meaning is the same as the base words.
Step 4, test the wrong form. Gave a decision reply is a noun where an adjective is needed. It could not describe reply. The position test catches this.
The mistake to watch for
Mistaken answer: The company was very success last year.
Success is a noun. After was very, the sentence needs an adjective.
Correct it as The company was very successful last year. Another common slip is using a noun where a verb is needed, as in They decision to move, which should be They decided to move. Always say the slot role aloud before writing the word: noun, verb, adjective or adverb.
Check yourself
1. Fill the gap: The hotel staff were extremely ______ (help).
Show answer
helpful. After were extremely we need an adjective that describes the staff.
2. Fill the gap: Careful ______ (prepare) will reduce your stress before the test.
Show answer
preparation. The gap is the subject of will reduce, and careful before it is an adjective, so a noun is required.
3. Choose the correct word: An (economic / economical) car uses very little fuel.
Show answer
economical. It means saving money or resources. Economic relates to the economy, so it would change the meaning. Two adjectives from one family can differ in meaning.
Where this leads next
The last skill in this module is to shorten a sentence without losing an essential condition, which often uses nouns such as cancellation in place of clauses. Try the mixed sentence practice set, and record word-form slips in the mistake log and retest queue.
Word-form errors usually come from habits formed over years. A teacher reading your real sentences can hear which families you confuse, and that is part of online one-to-one English as a Second Language tuition.