There are four sentence functions in English: declarative, exclamatory, interrogative, and imperative.

1. Declarative sentences state an idea. They end with a period.

• Grasshoppers contain more than 60 percent protein.
• Insects are rich in necessary vitamins and minerals.
• Crickets are packed with calcium, a mineral crucial for bone growth.
• Termites and caterpillars are a rich source of iron.

2. Exclamatory sentences show strong emotions. They end with an exclamation mark.

• I can’t believe you left the car at the station overnight!
• What a mess you made in the kitchen!
• Our evening is ruined!
• The china is smashed!

3. Interrogative sentences ask a question. They end with a question mark.

• Who would eat bugs?
• Where did you put the eraser?
• Would you please help me with this package?
• What do you call this dish?

4. Imperative sentences give orders or directions, and so end with a period or an exclamation mark. Imperative sentences often omit the subject, as in a command.

• Take this route to save 5 miles.
• Clean up your room!
• Sit down and listen!
• Fasten your seatbelts when the sign is illuminated.