题目

下列命题是真命题的个数为（） ①两条直线被第三条直线所截，内错角相等. ②三角形的内角和是180°. ③在同一平面内平行于同一条直线的两条直线平行. ④相等的角是对顶角. ⑤两点之间，线段最短. A . 2 B . 3 C . 4 D . 5 答案：B 阅读理解 　　The South China tiger could become extinct within 30 to 50 years if it does not receive protection．There are only 20 to 30 South China tigers in their earliest natural places, with Guangdong Province having only five left because forests are being destroyed as a result of rapid industrial growth． 　　The South China tiger can live 20 to 25 years, but the survival rate for the young is becoming lower as a result of rapid growth in industry and tourism．Even with hard work, it is hoped that the number of South China tigers can only reach 150 to 180 in the coming century． (1) The underlined word “extinct ” means ________． [　　] A． different B． seriously ill C． no longer exist D． frightening (2) The best title for this news could be ________． [　　] A． The Life Span of the South China Tiger B． The Coming Century for the South China Tiger C． Chinese Scientists Call SOS for South China Tigers D． Industrial Growth－The Enemy of South China Tiger