1. Relative Clauses Author: Teacher Boussoualim Malika
Complex sentences
Relative Clauses
Author: Teacher Boussoualim Malika

2. Relative clauses Function and meaning Position
Relative clauses (also called adjectival clauses) function like adjectives because they describe a noun phrase. They always follow the noun phrase and are introduced by relative pronouns (who, that, whom, whose, where (=at which, in which), which, and when).
Position
Relative clauses can come
after the main clause if they qualify the whole clause or the last part of it,
A gateway is an interface that enables dissimilar networks communicate.
Bridges can partition a large network into two smaller ones and connect two LANs that are nearby each other.
Embedded in the main clause if they qualify the subject,
Computers which are linked to a server are part of a network.
In a network, computes, which are sharing the same devices, can be infected due to a server infection.

3. Relative clauses Types of relative clauses
They are divided into defining (restrictive) and non-defining (nonrestrictive) clauses.
Defining relative clauses give essential information about the noun phrase it describes . No commas are used to separate the main clause and the subordinate defining relative clause.
A gateway is an interface that enables dissimilar networks communicate.
Non-defining relative clauses always present nonessential information to the understanding of the noun phrase referred to. Their function is to comment on the noun phrase, and they are set off by commas.
Each computer in a wireless network requires a wireless network interface card (NIC), which can be built in the computer.

4. Relative clauses Reduced relative clauses
When a relative pronoun is followed by a form of the verb be (is, was, has been, we often leave out both the pronoun and this verb.
A NIC, [] a wireless interface card, allow each computer in the network to communicate with a wireless local area network. (which is)
We often ‘reduce’ relative clauses which include a passive verb to obtain a past participle clause (-ed participle). We leave out the relative pronoun and the verb be.
A bridge is a hardware and a software combination [ ] used to connect the same type of networks. (which is)
We avoid reduced forms of future tenses.
Computers which will be used in the future might surpass human intelligence.
*Computers [] used in the future might surpass human intelligence. (Incorrect reduction)
We also reduce relative clauses with active verbs to obtain a present participle clause (-ing clause). We leave out the the relative pronoun and the verb be followed by an -ing verb, or we simply change the main verb into a present participle verb.
In a network, computes, [] sharing the same devices, can be infected due to a server infection. (which are)
A gateway is an interface [] enabling dissimilar networks to communicate. (which enables)