When a new disease breaks out, experts must __________ what to do in the fastest way.
183. This plan will help to _______ two birds with one stone.
182. In the time of great trouble, the soldiers _______ their spirits by singing.
181. The old man told us most of the story, but _______ the part about the murder.
180. The monkey came down and _______ onto the elephants back.
179. Please don’t _____ a joke on the disable. We should try our best to help them.