The Prime Minister has shown a disposition to alter policies

首相有意改变政策

They had to alter the course of the stream and obstruct the natural flow of the water.

他们得改变溪流的水道，阻止河水自然流淌。

The parts he disliked he would alter and the parts he didn't dislike he'd leave.

不喜欢的部分他要改变，并非不喜欢的部分他则留下。

The study shows how television and, by extension, the media, alter political relationships.

研究表明电视，乃至整个媒体是如何改变政治关系的。

In translation, one should not alter the meaning of the original to suit one’s own taste.

翻译时不应根据自己的好恶改变原文的意思。