4 Complete the definitions 1-5 using relative pronouns (who, which, that) and the informationin a-e.1 The CPU is a chip2. A hacker is a person3 A modem is an electronic device.4 A software engineer is someone5 The mobile phone is a devicea it enables a computer to communicate with another overtelephone linesb he/she writes computer programsc people use for communicating with each otherd it acts as the brain of a computere he/she invades a network's privacy заранее

1 The CPU is a chip **that acts as the brain of a computer**.
To answer this question, we need to find a relative pronoun that can connect the two parts of the sentence. The part before the comma describes the CPU, and the part after the comma provides additional information about the CPU. In this case, we use the relative pronoun "that" to connect the two parts.

2. A hacker is a person **who invades a network's privacy**.
Again, we need to find a relative pronoun that can connect the two parts of the sentence. The part before the comma describes a hacker, and the part after the comma provides additional information about a hacker. In this case, we use the relative pronoun "who" to connect the two parts.

3. A modem is an electronic device **that enables a computer to communicate with another over telephone lines**.
The relative pronoun "that" is used here to connect the two parts of the sentence. The part before the comma describes a modem, and the part after the comma provides additional information about a modem.

4. A software engineer is someone **who writes computer programs**.
The relative pronoun "who" is used here to connect the two parts of the sentence. The part before the comma describes a software engineer, and the part after the comma provides additional information about a software engineer.

5. The mobile phone is a device **which people use for communicating with each other**.
For this sentence, we use the relative pronoun "which" to connect the two parts. The part before the comma describes a mobile phone, and the part after the comma provides additional information about a mobile phone.

In summary, we use relative pronouns like "who," "which," and "that" to connect the main clause with a subordinate clause that provides additional information or describes the noun mentioned in the main clause.