题目

小宇用如图所示装置将一细光束斜射到空气中,用于探究“光的折射规律”。 （1）为了更清晰地观察水中的光路,可以采用的办法是:      ，实验中              （填“能”或“不能”）看见反射光线。 （2）实验的折射光路如图所示,可以判定折射角        (填“大于”、“小于”或“等于”)入射角。增大入射角，观察到折射角在           （填“增大”或“减小”）。 （3）他通过查阅资料发现，若不断增大光在水中的入射角，会 Valentine's Day is a very old holiday. It goes back to the times of Ancient Rome (古罗马)．One of the characters we often see on Valentine's Day is Cupid. He was the son of Venus, the goddess of love. He shoots people with arrows (箭) of love. When a man and a woman are hit by his arrows, they will fall in love. Today people celebrate Valentine's Day on February 14.If a man and a woman are in love, they will give each other gifts. The most popular gifts are flowers (especially roses) and chocolates. Couples may also go to a restaurant for a very nice dinner or plan something else romantic. In the United States, Valentine's Day is not just for lovers. Children make special Valentine's cards for their classmates. Families and friends may give candy or other small gifts to each other. It can be a fun day.1.Who is Cupid?A. The arrow of love.B. The goddess of love.C. The son of the goddess of love.D. The first person to celebrate Valentine's Day.2.When a man and a woman are hit by Cupid's arrows, they will ________.A. fall in love B. get gifts from GodC. hate each other D. fight each other3.What are the most popular gifts on Valentine's Day?A. Roses and chocolates. B. Roses and cakes.C. Arrows and cakes. D. Cards and chocolates.4.What do school children in the United States do on Valentine's Day?A. They plan something else romantic.B. They make special cards for their classmates.C. They go to a restaurant for a very nice dinner.D. They give candy or other small gifts to each other.5.From the passage, we can NOT get information about ________.A. the date of Valentine's Day B. the most popular giftsC. the story of Valentine's Day D. the feelings of classmates and friends