Because of the cruelty involved,scientists could never carry out this test on humans.由于这种做法的残忍性，科学家永远不会在人类身上做这样的实验

because of因为； 由于

She could only croak because of her heavy cold.

她因患重感冒只能用沙哑的声音说话。

The war was lost because of a shortage of munitions.

战争因军火不足而失败。

The best scientists could hope for would be to find real live case studies,科学家能期望的顶多是找到这样的实例来研究

hope for希望； 期待

We all hope for an improvement in the weather.

我们都希望天气好转。

We hope for some gain from our investment.

我们希望投资有利可图。

feral children, those brought up by animals in the wild.比如在野生环境下由动物抚养长大的孩子

bring up教育；养育

The couple contrived to bring up their children on a small income.

这对夫妻设法以菲薄的收入把孩子扶养成人。

The lamb had to be brought up by hand.

这只小羊要用奶瓶喂养。