1.【解析】isknown。考查动词时态、语态和主谓一致。beknownas为固定搭配,意为“被誉为”,句子描述客观事实,时态用一般现在时,主语YaoJianping为单数,故填isknown。2.【解析】that/which。考查定语从句。先行词为pictures,指物,在从句中作主语,故用关系代词that/which引导定语从句,修饰先行词,故填that/which。3.【解析】organization。考查词性转换。空前为形容词big和名词world,需填名词。organize的名词形式为organization(组织