Из активного задатка сделать пассивный 1. We must separate these impurities

Из активного заклада сделать пассивный 1. We must separate these impurities from the metal. 2. We could not distinguish the liquid alloy from a single one-substance liquid. 3. They will have to separate iron from sulphur with a magnet. 4. We may use metals in the main parts of structures or machine tools. 5. They had to cast metals into varied shapes.