These questions ask whether a relative form may safely disappear or must remain. Solve them by checking the clause type and then locating the subject, verb and missing role inside the relative clause.
Use the clause-and-gap test
First decide whether the clause identifies its antecedent or merely adds information. Omission is possible only in an unpunctuated defining clause. Next read the words inside that clause. If a noun or pronoun already performs the verb's action and the antecedent receives that action, the missing relative form is an object and may be left out. In the parcel Jo sent, Jo is the subject of sent and parcel fills the object gap.
| Internal pattern | Decision |
|---|---|
| The relative form performs the action | Keep it: the driver who waved stopped. Without who, waved has no subject inside the relative clause. |
| Another noun performs the action and the antecedent receives it | Omission is possible in a defining clause: the article Mira edited. |
| The clause is non-defining | Keep the relative form even when it is an object: Elm House, which we visited, has reopened. |
| A preposition stays at the end | An object form may be omitted in a defining clause: the colleague I spoke with. This stranded-preposition pattern is standard. |
| A preposition moves before the relative form | Keep which for a thing or whom for a person: the colleague with whom I spoke. Do not use who or that immediately after the fronted preposition. |
A useful final check is to place a silent gap after the verb or stranded preposition. If the antecedent naturally fills that one object position, the contact clause works. If the gap would need to perform the action, or if the clause is enclosed by commas, restore an explicit relative form.
Where omission goes too far
| Trap | How to reject it |
|---|---|
| A subject relative form is deleted because the clause is defining | Defining status is only the first condition. If no other subject appears before the relative verb, the form must stay. |
| An object form disappears from a comma-set clause | Non-defining relatives never use the contact-clause omission pattern. Keep the wh-form and both comma boundaries. |
| An ordinary object pronoun is added after a valid omission | The antecedent already supplies the understood object. Adding it, him, her or them fills the same role again. |
| A preposition is fronted but the relative form is still omitted | Fronting requires an expressed which or whom. Omission works only with the standard stranded-preposition pattern. |
| Commas are added simply because the contact clause feels like a pause | Punctuation follows meaning, not speaking rhythm. An identifying contact clause remains attached to its antecedent without commas. |
Try it
Select the defining clause with valid object-pronoun omission and no doubled object.
- The laptop, Mara recommended, is discounted.
- The laptop Mara it recommended is discounted.
- The laptop Mara recommended it is discounted.
- The laptop Mara recommended is discounted.
Required-pronoun check: select all sentences in which the relative pronoun must remain in ___.
- The guide ___ knows the trail is waiting.
- The article ___ the editor rejected was revised.
- The bakery ___ we visit closes at six.
- Big Ben, ___ millions recognize, is in London.
Complete the defining contact clause and leave the preposition at the end: This is the scheduling problem ___. Use exactly I, told, you, about, and earlier in that order, with no added words.