Fresh flowers actually continue to grow while in a vase．So in order to keep flowers fresh

Fresh flowers actually continue to grow while in a vase．So in order to keep flowers fresh, you need to consider what the flowers need to grow and stay healthy．Flowers need water, light, and food．Besides, you need to be aware of a few precautions to take．
Distilled water（蒸馏水） is the best kind of water to use for fresh flowers, because there are no chemicals in it．Change the water for your fresh flowers every day or no less than every 2 days to prevent bacteria（细菌） building up．Cut the stems under water again before putting them back in the vase, so that they will be able to draw water up easily．
Keep your fresh flowers out of direct sunlight．At night, put them in the fridge．This will prolong their life．Adding mercial flower food to good water is probably the best method of keeping flowers fresh．Some people put sugar in the water for food．That is OK, but mercial flower food has bacteria-killing ingredients, which can make the water more acidic（酸性的）．If you want a more natural food for your fresh flowers, try water that has been specially treated．That solution will also give the water acidity, sugar, and bacteria-killing ability．
Keep your fresh flowers away from fruit．Fruit gas, or ethylene, will reduce the life of your fresh flowers, making them get older faster．Ethylene is what makes fruit ripen．It is given off by dead flowers, too, so be sure to remove them．
If you follow these tips, your fresh flowers will last a long time and beautify any room in which you put them．
1．What does the underlined word precautions in Paragraph 1 mean?
A．problems that happen to flowers． B．advantages of having flowers．
C．measures taken to prevent problems．   D．preparations to grow flowers outside．
2．The fact that distilled water is most beneficial for fresh flowers indicates that     ．
A．distilled water is perfect for people to drink
B．running water shouldn’t be used to water flowers
C．it takes great efforts to keep flowers fresh
D．fresh flowers aren’t used to certain chemicals
3．In order to prolong the life of fresh flowers, you should     ．
A．protect them from direct sunlight during the daytime
B．put them in a damp place at night
C．put them in a fridge all the time
D．put them near water during the daytime
4．Which of the following is the best method of keeping flowers fresh?
A．Cutting the stems under water before putting them back．
B．Using distilled water and mercial flower food．
C．Keeping them away from fruit gas．
D．Watering them with water which contains sugar．C