二传在比赛中主要的作用是（）。A.接发球 B.防守 C.组织进攻 D.拦网
题型：单项选择题
问题：
二传在比赛中主要的作用是（）。
A.接发球
B.防守
C.组织进攻
D.拦网
题型：单项选择题
（B）
What does an astronaut eat in space? This is a question that will puzzle many, as people rarely think of that. In the early space-travel years, astronauts ate dehydrated (脱水的) foods that were eaten through straws （吸管）. In today’s space-age, the food that they eat is totally different. They eat food in the same way as people do on Earth.
Astronauts are able to prepare and eat a variety of foods in space. Some can be eaten in their natural form, like fruits, while some need to add water, like noodles. However, there are no refrigerators, so the food has to be prepared and eaten without being stored for a long time. When the astronauts are hungry, they simply eat the food by opening the food packages and with a fork, knife, and spoon.
Just like people on Earth, astronauts also eat three meals a day which include breakfast, lunch and dinner. Sometimes they also eat snacks. The US space agency NASA has found out that an astronaut’s diet reduces by about 70% on a space mission, though he has a wide range of foods to choose from like nuts, chicken, beef, seafood, and candies. Drinks in the spaceship include coffee, tea, juices, and lemonade.
Astronauts can also request a particular food that they would like to have in space. Scientists are always experimenting and trying out different space foods that can be offered to astronauts when on space missions.
45. Now astronauts eat ________ in space.
A. dehydrated (脱水的) foods B. food as people do on Earth
C. totally different D. food with a lot of water
46. The food the astronauts prepared ________ .
A. can’t be stored for a long time B. can be put into refrigerators
C. can be stored for a long time D. can’t be kept in the food packages
47. In space, astronauts ________ like people on Earth.
A. only have nuts, chicken and beef B. onlyhave lunch for a day
C. only drink coffee, tea and lemonade D. also eat three meals a day
48. What are scientists experimenting and trying out?
A. Some very special snacks. B. How astronauts can sleep well.
C. Different space foods for astronauts. D. How to get some fruits for astronauts.