A、It is easier to use. B、It can last longer. C、It becomes colorful. D、It becomes delicate. B文章末尾提到制造商需要更浓的油使口红使用的时间更持久，B正确。表示目的的

Lipstick plays an important role in sexual attraction and can even protect the lips from drying out in harsh weather: No wonder it’s the most important item in a woman’s cosmetics bag. Around 50 per cent of all women wear lipstick. Coloring the lips is certainly not a new idea. Evidence suggests it was practiced as early as 3,500 BC. In the past, a natural dye was used to paint lips. It was not until the 17th century that lipstick manufacturing really took off. The lipstick was made of mixtures that included pig fat and red sandalwood. It was kept in tiny pots and applied with a coloring stick. Lipstick was invented and first shown by Parisian perfumeries in Amsterdam. But these "little red sausages" were less than practical. They were wrapped in silk paper and the ends had to be broken off before each use. They also did not come cheap. Over the years the sticks became less expensive and new colors were developed. But it was not until 1950 that lipstick was accidentally re-invented—this time by the Americans. Today there are so many types of lipsticks and shades that it is hard to keep track of them. Faced with the large number of choices in the cosmetic departments, it is easy to forget that there is a whole science to manufacturing them. The basic ingredients are colors, oils and waxes. But they can contain up to 30 different materials. Lipstick manufacturers have to achieve a delicate balance. They need a thicker oil to make the lipstick last longer, but a thinner one to make it easy to apply. Different oils also provide protection for sensitive lips, preventing them from drying up.
12. What can be learned about lipstick from this passage?
13. What did people use to paint lips in the past?
14. What was one of the disadvantages of the first lipsticks?
15. How is the lipstick if a thicker oil is employed in the materials?