The teachers often tell their pupils ____ across the road when the traffic light is red. 

—Sometimes, Jim feels stressed, but he doesn’t know _______ about it. —He can get help from his teachers.

— Everyone must __________ the security check (安检) before getting on the plane at the airport.— Yes. It’s necessary to ensure the passengers’ safety.

Paul’s parents were worried that he ____ too much time chatting on line.

Alice was ill, so her mother________ her at home.