【简答题】Now a paper in Science argues that organic chemicals in the rock come mostly from ________ on earth rather than bacteria on Mars. A) configuration B) constitution C) condemnation D) contamination
【简答题】阅读理解 Take any long piece of paper. Now glue the ends of the paper together. You have made a ring. Take a second long piece of paper. Twist the paper once and glue the ends together. Now you have made ...