Before the festival, people will clean up all the streets.

• This means that before the festival, people will make the streets clean.

The scientist will explain some techniques on how to reuse household things.

• This suggests that the scientist will teach people ways to use household items again instead of throwing them away.

Using public transport helps reduce traffic jams.

• Using public transport means fewer cars on the road, which helps to decrease traffic congestion.

The rescue team will take the elephants to another place so that they can save their lives.

• This sentence implies that the elephants are in danger and the rescue team is trying to protect them.

Please do not waste electricity because there will not be enough for us to use this winter.

• This is a request to conserve electricity because there is a shortage.