TOEIC Link Part 5: complement versus supplement
Complement and supplement both point at the idea of adding, and both work as a noun and a verb in business English, yet they add in different ways. Complement means to complete something or go well with it, so the parts fit together into a finished whole. Supplement means to add an extra amount on top of what is already there, so the base stays and more is layered onto it. Part 5 drops one into a sentence about how two things relate, so it checks whether the blank means completes / matches or adds extra. For the wider set of look-alike traps, start with the commonly confused word pairs master index.
The core rule: completes versus adds extra
- complement = to complete something or fit well with it (verb; also a noun meaning the thing that completes). The new hire's design skills complement the team's technical strength. / A crisp white wine is the perfect complement to the dish. It answers what makes the whole feel complete? Link complement to complete and match: a complement brings the missing piece so the set works together.
- supplement = to add an extra amount on top of an existing base (verb; also a noun meaning the added portion). She supplements her salary with freelance work. / The report includes a data supplement at the back. It answers what extra was added on top? Link supplement to extra and add on: a supplement is more of something, layered onto what you already have.
The spelling carries the hook: complement shares its first letters with complete, and both are about making something whole; supplement shares its root with plus and surplus, both about an added extra. If the blank means the pieces fit together into a finished whole, it is complement; if it means adding more on top of a base, it is supplement.
Why Part 5 likes this pair
Because the two words overlap in the general idea of "adding," only the exact meaning separates them. If the blank describes two things fitting together to complete a whole, you need complement. If the blank describes adding an extra amount on top of something, you need supplement.
Her calm manner and his energy __ each other perfectly on the sales floor.
A word meaning complete / go well together needs complement.
The company decided to __ the training budget with an outside grant.
A word meaning add extra on top needs supplement.
Spotting the clue
Decide whether the blank is a completes word or an adds-extra word:
- Does the blank describe two parts fitting together into a finished whole? → choose complement (skills that complement the team, a color that complements the logo, the perfect complement to the meal).
- Does the blank describe adding a further amount on top of a base? → choose supplement (supplement your income, supplement the diet, a supplement to the main report).
A quick test: can you replace the blank with completes or goes well with, as in skills that complete the team? Then it is complement. Can you replace it with adds extra to, as in add extra to your income? Then it is supplement. The relationship is the tell: complement is about fit and balance between things, while supplement is about quantity added to one thing. Because both are add-related nouns and verbs that trip up test-takers, this pair sits alongside the other traps in the sound-alike verb pairs study guide.
Common Part 5 patterns
- Anything about fitting together or completing wants complement: skills that complement the role, a complementary color, the wine is a fine complement, their strengths complement one another.
- Anything about adding an extra amount wants supplement: supplement the budget, supplement the workforce, a dietary supplement, a supplementary appendix.
- Meaning cue: a sense of balance and fit leans complement; a sense of extra quantity on top leans supplement.
If the blank means completes or goes well with, choose complement. If it means adds an extra amount on top, choose supplement.
Quick recap
- Complement = to complete something or fit well with it — her skills complement the team.
- Supplement = to add an extra amount on top of a base — she supplements her salary with freelance work.
- Part 5 test: swap in completes / goes well with → complement; swap in adds extra to → supplement.
Sort the completing from the adding-on-top, and this quiet pair stops costing you Part 5 points. Keep working through the commonly confused word pairs master index to lock in the rest.