专业英语汉译英

第一单元

1.太阳系八大行星中，一般把水星、金星、地球和火星称为类地行星，它们的共同特点是其主要由石质和铁质构成，半径和质量较小，但密度较高。

Among the eight planets in the Solar system, Mercury, Venus, Earth and Mars are called the terrestrial planets. All of them consist of lithoid and ferruginous materials mostly with relatively smaller radius and mass and higher density .

2.太阳系是由受太阳引力约束的天体组成的系统，它的最大范围约可延伸到1光年以外。The Solar system consists of objects restricted by solar gravitation and its maximal bound may exceed 1 light year.

第二单元

太阳系中的八大行星（水星、金星、地球、火星、木星、土星、天王星、海王星）都在接近同一平面的近圆形轨道上朝同一方向绕太阳公转。

Eight planets of the Solar system orbit the Sun in or near the same plane with nearly circular orbits and in the same direction.

地球绕太阳公转的速度为每秒30公里，绕太阳一周需要365天5时48分46秒，也就是一年，天文学上称之为回归年。

Earth revolution takes 365 days 5 hours 48 minutes and 46 seconds or one year, called the tropical year on astronomy to revolve around the Sun one cycle with a speed of 30 kilometers a [per] second.

这就说明，四季的变化与近日点和远日点无关。

This phenomenon indicates that the seasons have nothing to do with the perihelion and the aphelion.

第三单元

我们生活的地球是一个形状像梨一样的椭球体，它的赤道半径6378 km，极半径6357 km，平均地球半径6371 km，总质量5.976×1024 kg

The Earth we live on is a pear-shaped ellipsoid with an equatorial radius of 6378 km，a polar radius of 6357 km，an average radius of 6371 km and a total mass of 5.976×1024 kg.

下地幔的主要物质组成为Mg（32%）、FeO（18%）、SiO2（50%）（32%）、FeO（18%）、SiO2（50%），下地幔处于高温高压状态，温度约为3700℃。压强从23.8 GPa增大到135.7 GPa。The lower mantle is at a high temperature and pressure condition and the temperature is about 3700℃and the pressure is from 23.8 GPa to 135.7 GPa.

第六单元

地球上的水资源以气态、液态和固态在陆地、海洋和大气间不断循环。

Water resource on the Earth is continually cycled between landmasses, oceans and atmosphere as gas, liquid and solid.

这种不平衡可通过由陆地流入海洋的水而补偿，河流是陆地上的水流向海洋的主要通道。

This imbalance can be compensated by water flowing from the landmasses to the oceans and rivers are the main channels in which water flows from the landmasses to the oceans.

第七单元

河流地貌是河流作用[于地球表面]，[经侵蚀、搬运和堆积过程所形成]的（各种侵蚀、堆积地貌的）总称。

Fluvial landform is the general term（of various types of erosion and accumulation landforms）（produced by fluvial processes）[on the surface of the Earth][through erosion, transport and deposit].

河流阶地是河流地貌中重要的地貌类型，可以分为侵蚀阶地、堆积阶地、基座阶地和埋藏阶地。

Fluvial terrace is an important type of fluvial landform which is composed of erosion and accumulation terrace, basement terrace, and buried terrace.