根据句意,用括号内所给单词的正确形式填空。 1. This costume is made of ____ (nature) material. 2. Today ____ (near) every family in our country has a TV set. 3. In ____ (north) parts of America, people often wear warm clothes in winter. 4. The machine should be ____ (heat) before we use it. 5. As the old ____ (say) goes, 'Time waits for no man!'