Though he was very young, he knew how to behave well.
倒装后是①还是②：
① Young though he was, he knew how to behave well.
② Very young though he was, he knew how to behave well.
另外，③和④什么是正确的？
③ Though he was very young, he knew what the right thing was.
④ Though he was very young, he knew what was the right thing.
又，⑤、⑥、⑦、⑧什么正确？
⑤ Though he was very young, he knew what the right thing to do was.
⑥ Though he was very young, he knew what was the right thing to do.
⑦ Though he was very young, he knew what the right thing was to do.
⑧ Though he was very young, he knew what was right.
自己瞎想出来的几个问题，回答不了，请不吝赐教！
Though he was very young, he knew how to behave well.
这种句子不是倒装，而是表语前置。
① Young though he was, he knew how to behave well.
② Very young though he was, he knew how to behave well.
表语前置本身就是强调，因此没必要再用very。故第一句正确，第二句欠妥。
③ Though he was very young, he knew what the right thing was.
④ Though he was very young, he knew what was the right thing.
这二句均正确，由于这是确认性表语，主语和表语可以互换句法功能。比如：
This is the right thing. 改为问句：What is the right thing？ what就主语提问，句子无倒装。去掉问号即为名词性从句what is the right thing
The right thing is this. 改为问句：What is the right thing? what就表语提问，is 倒装。去问号、去倒装，则得到名词性从句what the right thing is
⑤ Though he was very young, he knew what the right thing to do was.
⑥ Though he was very young, he knew what was the right thing to do.
以上二句均正确。道理同3、四句，确认性表语。
⑦ Though he was very young, he knew what the right thing was to do.
错误，应改为第5或第6句。
⑧ Though he was very young, he knew what was right.
正确。形容词作归属性表语。
