听下面一段材料，回答第至3题。. What are the 

题目描述

听下面一段材料，回答第至3题。. What are the speakers mainly talking about?[ ]2. What might the balls most probably be used for?[ ]3. Why have astronauts made the ball in space?[ ]

A、A research plan made in space.

B、A certain ball made in space.

C、A problem in making things in space.A. Children's games B. Earth protection C. Medical researchA. To keep them smaller B. To keep them perfectly round C. To produce them more cheaply

本站整理有大量高等教育、资格考试类试题答案，Ctrl+D收藏备用!