Could you please ________ how the machine works— Of course.

In case it thunders, we’d better _____________ the electricity at once and turn off the TV.

Sir, you ______use your mobile phone at the gas station. It’s very dangerous.

My mom, who didn’t allow me to smoke, ______ when she caught me smoking.

All of us must do_______ to help protect the environment，or we will have more hazy weather雾霾天气.