求教TPO16第三篇阅读的第四题

liyangchinaUID: 2612429

Other dimensions along which the two groups differ markedly are density and composition. The densities of the terrestrial planets average about 5 times the density of water, whereas the Jovian planets have densities that average only 1.5 times the density of water. One of the outer planets, Saturn, has a density of only 0.7 that of water, which means that Saturn would float in water. Variations in the composition of the planets are largely responsible for the density differences. The substances that make up both groups of planets are divided into three groups—gases, rocks, and ices—based on their melting points. The terrestrial planets are mostly rocks: dense rocky and metallic material, with minor amounts of gases. The Jovian planets, on the other hand, contain a large percentage of the gases hydrogen and helium, with varying amounts of ices: mostly water, ammonia, and methane ices.

答案选A，我觉得B可能正确。因为文中并未直接比较saturn与其他T星球的密度，但文中最后一句表明J星球的组成，其中不含rocket（虽然并没有直接这样说）

wonderful.2010UID: 2775319

我看了另一个版本的，答案就是B，没有rocky metals
1# liyangchina

温情的驴UID: 2943479

The substances that make up both groups of planets are divided into three groups—gases, rocks, and ices—based on their melting points.注意BOTH。说明所有行星3种物质都有。