下列关于植物体的组成和细胞结构的叙述,不正确的是( ) A . 有的植物细胞中没有叶绿体 B . 西瓜在结构层次上属于组织 C . 植物体的各种组织是经过细胞分化形成的 D . 表皮破损的番茄很快腐烂是保护组织遭到破坏的缘故 答案:B18、From April 1, 2009, 3G mobile phones ______ in 8 main
cities in China ________of what is going on all over the world faster and more
conveniently..
A. are used; to keep
informed
B. have come into use; to keep people informed
C. come into use;
keeping informed D. have been in use; informed