8, It has been estimated that if the bridge were packed with cars, it would still only be carrying a third of its total capacity.

It has been estimated / expected that…据估计

同种结构的句型还有：It is said that…\It is reported that 据说\据报道

be packed with... = be full of 作“挤满......; 装满 ......”解

were  虚拟语气（桥上不可能摆满汽车的）

carry 承载

a third of ……的三分之一

9，Despite its immensity, it is both simple and elegant, fulfilling its designer's dream to create 'an enormous object drawn as faintly as possible'.

immensity: size

despite==in spite of新概念英语第二册1

fulfilling: 现在分词做结果状语，表示一种主动的概念,即动作的实施者正是主语。

e.g. The bus was held up by the snowstorm, causing the delay.

e.g. Her husband died in1970, leaving her with two children.