We work together to achieve our common purpose: ____ world that is safer, cleaner and healthier than ____ one we founded.
Her work changed the way _______ people think about chimps.
The Voice of America began during the World War Ⅱ, when Germany was broadcasting a radio program to get international ______.
The officers narrowly escaped ___________in the hot battle.
The children do not know how to _______ themselves decently at the party.
The teacher said there were twelve _____ who had failed in the exam.