Reduced relative clauses

A relative clause comes after a noun and tells you which person, thing, or group you mean. In the customers who ordered online, who ordered online gives extra information about customers. Before reducing the clause, identify that noun and the relationship between the noun and the verb.

The customers who ordered online will receive a confirmation email.

Customers do the ordering. That active relationship helps you choose an -ing form in the reduced version.

Which noun does who ordered online describe?

It describes the customers, not the email.

When the noun is the person or thing that performs the action, you can often remove who, which, or that and use an -ing form. This is especially common when the full clause uses be plus an -ing verb, but it can also reduce a simple present clause in many descriptions.

The woman standing near the window is our new manager.

The woman is standing near the window, so standing has an active meaning.

People living near the airport may hear late flights.

People live near the airport. The -ing form describes their usual situation here.

Choose the reduced form: the guests who are waiting outside or the guests waiting outside?

The guests waiting outside is correct because the guests perform the action of waiting.

Use a past participle when the noun receives the action. The package delivered this morning means the package that was delivered this morning. The past participle does not always mean that the action happened in the past. It shows the passive relationship; the surrounding words often show the time.

The equipment stored in this room belongs to the science department.

The equipment is stored in this room. It receives the action, so stored is passive.

Meals prepared by the kitchen team are labeled clearly.

The kitchen team prepares the meals. The meals receive the action.

Which form is passive: the files saved on the server or the files saving on the server?

Use the files saved on the server because someone or something saves the files.

A to-infinitive can reduce some relative clauses after ordinal words, only, or a superlative. The last person to leave means the last person who left. This pattern often describes an order, a result, or a task that a particular person must do.

She was the only candidate to answer every question.

Only identifies one candidate. To answer gives the action that makes that candidate unique.

This is the safest place to wait during the storm.

After a superlative such as safest, to wait can identify the purpose or action connected to that place.

Choose the compact form: the next customer who will be served or the next customer to be served?

The next customer to be served is a common reduced form. The customer receives the service.

Do not reduce every relative clause. A full clause can show a specific past time, a modal verb, a negative, or a condition. The employees who must wear safety glasses cannot become the employees must wearing safety glasses. Keep the full clause when the reduced form is not grammatical or would make the meaning less precise.

The files that were not included in the email are on the shared drive.

Files not included in the email can work in a formal style, but the full clause may be clearer when the missing status is important.

The neighbors who lived here before us moved to another town.

Lived here before us gives a completed past situation. The phrase neighbors living here would refer to people who live here now.

Can you reduce the employees who must wear safety glasses to an -ing phrase?

No. Must carries an important requirement, so keep the full relative clause.