1.
a first-,,second-,,third-rate job
一等、 二等、 三等的工作
2.
What class (of degree) did you get: first, second or third?
你获得哪一等（学位）：一等，二等，还是三等？
3.
What class did you get, first, second or third?
你得的是几等学位？一等，二等还是三等？
4.
an ordinary seaman
[英](=[美]anapprenticeseaman)三等水兵
5.
One, two, three, etc. are the cardinal numbers.
一、二、三等是基数。
6.
To divide into three equal parts.
把…三等分,把…分成三份
7.
Two is to three as four is to six.
二比三等于四比六。
8.
to travel third class
乘三等车（或舱）旅行
9.
Be awarded the Third-Class People's Scholarship
获人民奖学金三等奖
10.
triangular pediment
成等边三角形的三角墙
11.
an equilateral triangle
等边三角形,正三角形
12.
Multiply three By four gives twelve.
三乘以四等于十二。
13.
divide the cake into three equal parts; The British carved up the Ottoman Empire after World War I.
把蛋糕分成相等的三份。
14.
(of a triangle) having two sides of equal length.
（三角形）有二等边的。
15.
a triangle with two equal sides.
有两条边相等的三角形。
16.
a square equivalent to a triangle
同三角形等积的正方形
17.
It was obvious that it ought to be divided into three equal parts.
应该分成等量的三块。
18.
a three-sided regular polygon.
有三条边的等边多角形。