Mercury, Venus, Earth, and Mars are called "rocky planets".水星、金星、地球和火星被称为“岩石行星”。Mercury's orbit is fairly eccentric.水星轨道的离心率相当高。The surface of Mercury seems to consist largely of dust.水星的表面似乎大部分由尘埃构成。Mercury is the smallest of all the planets.水星是行星中最小的一颗。