1. Not only is every step of climbing Mount Qomolangma felt by the viewer, but also the cold, the tiredness, the food, the smells, the sights and the sounds of the mountain can all be experienced.
观众不仅能感觉到爬珠穆朗玛峰的每一步，而且能体验到寒冷、疲惫、食物、气味、风景以及山上的声音。

     not only…but also… 意为“不仅…而且…”， not only位于句首，其所在分句用部分倒装。not only…but also…连接并列主语时，谓语遵循“就近原则”。but also中的also也可省去；but also也可换为but…as well。

He likes not only English but also Chinese.
=Not only does he like English, but also Chinese.
他不但喜欢英语，也喜欢汉语。

Not only I but also she likes pop music.
不但我而且他也喜欢流行音乐。

This book is not only interesting but (also) instructive.
这本书不仅有趣，而且有教育意义。

2. He finally stops thirty million years into the future and experiences a future time where the sun no longer shines brightly.
最后，他们停止在未来的3,000万年，体验了一个太阳不再照耀的未来时空。

     在这个句子中有两个并列的动作stop和experience。关系副词where用来引导定语从句，修饰前面的名词time,在从句中充当地点状语。如：

3. He’s got himself into a dangerous situation where he is likely to lose control over the plane.
他使自己陷入了一个很危险的境地，他有可能无法控制飞机。

4. I can think of many cases where students obviously knew a lot of English words and expressions but couldn’t write a good essay.
我可以想到在很多情况下，尽管学生掌握了大量的词汇但却无法写出一篇令人满意的文章。