The strength of nylon is two or three times higher than cotton, and four or five times higher than wool. Generally, a nylon wire with a diameter of 1 mm can lift 100 kg of things, and a nylon rope with a finger thickness can lift a fully loaded truck! The main words of this passage are:. ['Strength of nylon.', 'Uses of nylon.', 'The magic of nylon.', 'Comparison of nylon, cotton and wool.']