a. BECause the surface of mars seemed to be geometric. h|=^L$h(=AHfT#:Kl [ 本 资 料 来 源 于 贵 州 学 习 网 考研一方工程硕士 http://Www.gzU521.com ] h|=^L$h(=AHfT#:Kl

　　b. because the lines were drawn across the surface of the planet.

　　c. because a system of canals was thought to be there.

　　d. because it was the martians that built the canals.

　　22. the“canals”on mars have proved to be according to the passage.

　　a. the minor geologic characteristics of mars

　　b. natural valleys on the surface of mars

　　c. rivers that have kept flowing since ancient times

　　d. a system that irrigates the whole surface

　　23.what are the mars‘seasonal changes in color believed to be ？

　　a. the natural changes on the planet.

　　b. the seasonal cycles .

　　c. the movement of some life form .

　　d. the storm of dust in its atmosphere.

　　24. how is the 1996 discovery related to the possible existence of organisms on mars？

　　a. the meteorite containing organic compounds is part of mars.

　　b. a martian rock struck earth about 11，000 years ago.

　　c. the organisms came back to life after the collision with earth.

　　d. the inhabiting organisms appeared more than three billion years ago.

　　25. how many arguments in this passage lead to the belief of the existence of life on mars？v)SezqEG^{U0~.#,q=d[ 此文转贴于我的学习网考研一方工程硕士 http://www.Gzu521.com]v)SezqEG^{U0~.#,q=d

　　a. tow b. three c. four d. five

　　questions 26-30are based on the following weather forecast：