土卫四

There are no albedo features on Tethys as there are on Rhea and Dione.

像在土卫四和土卫五上一样，在土卫三上没有反照率特征。

From left to right are Enceladus and shadow, Dione and shadow, and Saturn's largest moon Titan.

从左至右是土卫二和阴影，土卫四和阴影，以及土星最大的卫星土卫六。

The cliffs may indicate that Dione has undergone some sort of tectonic surface displacements in its past.

这些冰崖表明在过去土卫四的表面可能经历了某种地壳运动。

Tethys' low density indicates that it is almost completely composed of water ice, similar to Dione and Rhea.

土卫三的低密度表明它是几乎全部由水和冰组成，这与土卫四和土卫五十分相象。

This suggests that during the period of heavy bombardment, Dione was tidally locked to Saturn in the opposite orientation.

这说明土卫四被撞击时它的正面和反面正好反过来。

Because Dione is relatively small, an impact causing a 35 kilometer crater could have spun the satellite.

由于土卫四比较小，在受到比较大的撞击（撞击坑大于35千米）时它会被转动。

Since there are many craters larger than 35 kilometers, Dione could have been repeatedly spun during its early heavy bombardment.

由于土卫四表面有许多大于35千米的撞击坑，因此它在早期撞击率比较高时可能不断被转动。

Farther to the left, and off Saturn's disk, are the bright moon Dione and the fainter moon Enceladus.

更远的左边的土星环上方，是明亮的土卫四狄俄涅和昏暗的土卫二恩克拉多斯(土星的卫星基本都是神话中的巨人啊，本文说的就是这4个卫星，注意后面的图上的黑点是阴影)。

This movie still captures the moons Mimas,Enceladus, and Dione as they begin their race across Saturn's disk.

本段视频是土星的几个大卫星在土星光环附近赛跑的截图片段（应该说这些是原始图像才对——译注），这三个卫星是土卫一、土卫二和土卫四。

Dione is on the far left of the image, Mimas is in the middle, andEnceladus is on the right. Dione and Enceladusare casting long shadowson the rings.

在图中，土卫四位于最左下方，中间的是土卫一，土卫二在右方。

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。