一对的

"And"应该"are quite different in emotional colouring and can not be used together.

"一定"和"应该"是一对感情色彩截然不同的词，不能并用。

I read somewhere the other day that in America one in three marriages now come to grief.

前日我在某一文中读到：现在在美国，三对夫妇中就有一对是不幸的。

Its compound eyes are also big, but small proportion to body.

一对复眼就跟一般见到的苍蝇差不多大了。

They are not even a couple. That made me a little released. Otherwise, I would be compunctious being a spare person in that group.

我原来一直以为的一对小情侣竟然只是好朋友，这让我压力小了好多，否则，我们三个人在一组，我一直觉得自己是个电灯泡。

It consists of a pair of concentric cylinder.

它由一对同轴的圆筒组成。

In June of 2004, he was also one of the surgeons who separated conjoined irginian girls.

在2004年6月，他也参与了一台分离手术，手术对象是一对来自弗吉尼亚的女孩。

Doctors in France are trying to separate a set of conjoined twins.

法国的医生正试图为一对连体婴进行分割手术。

Jason and Lee are digit buddies experience connatural lives in Vancouver.

Jason 和Lee是一对死党，他们在温哥华过着平静的生活。

Connecter that splits into three branches, showing a one-to-many relationship.

拆分为三个分支的连接线，表示一对多关系。

In Graph Theory,we shall also be interested in connected graphs in which there is only one path connecting each pair of vertices;such graphs are called trees（generalizing the idea of a family tree）.

在图论中，人们还对树感兴趣，树是每一对顶点间只有一条路的连通图。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。