5. Which of the sentences below are imperative? Mark them with “I”. 1) You made a mistake in the last exercise. 2) Set that box down on the floor. 3) You are afraid of dogs. 4) Put these envelopes in the mailbox when you go out. 5) You are not the brightest bulb in the lamp.

Imperative sentences are sentences that give a command, instruction, or request. Here, the imperative sentences are:

1. You made a mistake in the last exercise.

2. I — Set that box down on the floor.

3. You are afraid of dogs.

4. I — Put these envelopes in the mailbox when you go out.

5. You are not the brightest bulb in the lamp.

So the correct answers are: 2 and 4.