题目

Many countries, for example, Mexico and Japan, _____a lot of earthquakes.A. have    B. having    C. to have    D. having had 答案：A 解析: many countries是句子主语，横线处为句子谓语。水稻的体细胞中有24 条染色体，那么它的生殖细胞中的染色体数为(   )A．24条B．12条C．6条D．24对