【正文】
. an18. ________, I want to go to Mars! ( )A. A day B. One day19. But I can see ________ sun and other stars. ( )A. the B. a20. The Chinese space station ________ ready in 2022. ( )A. will be B. gets21. They will fly a rocket to ________. ( )A. the outer space B. outer衡石量書整理