(1) 这两个词容易混淆。high用作副词，意为“高，高度地”，多用于指具体真实意义的“高”，也可表示抽象、引申意义的“高”。

• He was climbing high when I saw him.
  我看见他时，他正爬得高高的。
• He lived high in all his life.
  他一生奢侈。
• He aims high in his political ambitions.
  他有很大的政治抱负。
• Popular passions ran high (=were strong).
  群情激昂。

 (2) highly意思是“很高地，高度地”，多用于修饰过去分词或形容词，常用于引申意义。

• The foreign guests were highly pleased. (此处的highly相当于very)
  那些外国客人非常高兴。
• They all speak highly of what we've accomplished.
  他们对我们取得的成就赞不绝口。

＊其他用法还有：a highly paid official, a highly amusing film, a highly developed industrial society, a highly skilled flier, a highly motivated student, a highly competent man, highly probable, highly scientific, highly confidential等。