School children must be taught how to deal with dangerous _________．

 It’s difficult for college students to have a train seat during holidays, so they are advised to make seat ________ well in advance.                     

When and where will it suit your ______ for our next meeting，Mr.Brown?

They discussed the issue of the world’s climate in Durban, South Africa several times but could come to no ________.

After careful research, it was decided that the spaceship should reenter the Earth’s________.