But nearly 100 million years ago relatives of modern snakes undulated through Cretaceous period waters aided by a paddlelike tail and dragging a pair of short, footless hind legs.
但是在将近1亿年前，现代蛇类的近亲们靠着它们船桨似的尾巴在白垩纪的水流里随波起伏，拖曳着它们短小而笨拙的后腿。
One of these designs has a pair of jet engines mounted aft, but positioned over and above the wing. This aircraft has no tail fins at all (see below).
其中一个设计方案有一对安装在尾部、在机翼上方的发动机，而根本没有尾翼（见下图）。
Larvae dark gray color, green or weak stomach abdomen only with three and a pair of tail foot.
幼虫深灰绿或淡青色，腹部仅有腹足三对及尾足一对。
In the experiment, a simplified aircraft model (with tail wing) is employed to construct a 4-vortex wake system consisting of a pair of tip vortices and a pair of counter rotating tail plane vortices.
试验采用简化的飞机模型(有尾翼)，建立了包含一对翼尖涡及一对反向旋转的尾翼涡(通过以负迎角安装尾翼得到)的4涡尾流系统。
A pair of small ears, a short tail, legs, short and thick, body hair black and white;
一对小小的耳朵，短短的尾巴，四肢又短又粗，身上的毛黑白相间；
The first and second-stage larvae were characterized by their abruptly thinned tail ends and the third-stage larvae were characterized by a pair of inverted U-like structures of the head.
第一、二期幼虫的特征为尾尖骤然尖细，第三期幼虫的特征为头部具一对倒“U”形棕色结构。
C. Officials corralled the white tail deer into an inflatable lifeboat and then released the pair at a nearby park.
官方把这2白色尾鹿放进一个充气式救生艇然后把它们放到附近的公园里。
Its face has a pair of slits that extend from the nostrils to just below its eyes, and its tail ends in a "t" shape.
他的脸上有一对狭长的裂口，从鼻孔一直延伸到眼睛下面，他的尾巴最终弯曲成一个“T”一样的形状。
Its face has a pair of slits that extend from the nostrils to just below its eyes, and its tail ends in a "t" shape.
他的脸上有一对狭长的裂口，从鼻孔一直延伸到眼睛下面，他的尾巴最终弯曲成一个“T”一样的形状。
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