题目

下列叙述正确的是( ) A.荒漠化是荒漠在原来基础上不断扩大的过程 B.气候因素特别是年降雨量的变化，往往影响着荒漠化的进程，对荒漠化的形成和发展起着决定性作用 C.经过20多年的治理，我国的荒漠化发展趋势已经有所逆转 D.我国是世界上荒漠化最严重的国家之一   答案：D  本题对荒漠化的发生、发展及其防治作了多角度考查。A选项主要是考查荒漠化发展过程，荒漠化不是简单的荒漠化扩张，而是很多块分散的土地逐渐退化，并最终连接在一起，形成如同荒漠化景观的过程；B选项考查荒漠化的形成，气候因素的确对荒漠化进程有很大影响，多雨抑制风沙活动，干旱则Ⅰ.牛刀小试：用括号中所给动词或词义的适当形式填空。【1】My father told me that two and two ____(be) four.【2】She said that there _____(be) many books on the desk.【3】He says that Tom ______(be) wrong.【4】Do you know when he ____________(come)?【5】Our father said that he ___________(buy) a new computer next week.【6】She asked me if I knew that light ____________(travel) much faster than sound.【7】This photo shows you _____my hometown ____（像…样子）in the past.【8】Eric asked his Chinese pen pal _______ he _____________（是否见过）Jiang Dawei himself with his own eyes.【9】I _________ think it ________________ （不会下雨）tomorrow.【10】_______________ （我想知道的）is which road we should take.