优质文档优质文档M3 U2 We have not found life on any other planets yet.1. Put the words in the right order from small size to big one.galaxy planet solar system star universe satellite_2. Draw a picture of the universe and put the words in the right places.3. You are the crew of a spacecraft and you are doing space research on Mars. Your spacecraft has just landed on Mars, and you have discoveredWhat we have done in space travel. _Some questions to our alien friends. _
