全部倒装:Here are some letters for you.还原后是否是 Some letter are he

全部倒装:
Here are some letters for you.还原后是否是 Some letter are here for you.
部分倒装:
Only today did i learn the dreadful news.还原后是否是 Only today i learned the dreadful news.
书上说There be 也是个倒装句 可我怎么看也没看得出来 如下这句:
There was an apple tree behind the house.
书上有说 neither /nor/so + be/have ,助动词或情态动词+主语,这一句型表示前面的内容也适用于另一个人或物
这里说的是不是 neither /nor/so + be/have 和 助动词或情态动词+主语 两个不同的句型的啊?
而下面的例子又好象两种都不是的,为什么的,
例:Rock music is OK ,and so is skiing.
Hardly had the sailors sighted land when they shouted happily.还原后是不是 the sailors had sighted land Hardly when they shouted happily.
Hardly意思不是决不吗?那这样还原后和书上的解释又不同了 ,书上该句的解释是 水手们一看到陆地就高兴得跳了起来
Only by changing the way we live can we save the earth.还原是不是 we can save the earth Only by changing the way we live.
那书上说该句用了部分倒装是怎么看出来的?
最后,下面这两个个倒装句是怎么翻译过来的(方法,具体怎么还原成正常语序):
Also present will be a person who thinks up an idea for an advertisement.
书上附的句意:出席会议的还有广告的策划者
They arrived at a house,in front of which sat a small boy.
Strange as it might sound,his idea was accepted by all the people at the meeting.那这个到底是什么倒装啊?又不是全部又不是部分的样子