highly

Compared meaning: very, to a high degree (adverb).

比较义项：非常，到很高的程度（副词）。

• highly 本词

  Formal and evaluative in tone; typically collocates with words expressing praise, approval, or professional assessment, such as recommended, skilled, or regarded; less common before ordinary adjectives like hot or tired.

  语气正式、带评价色彩；常与表示赞许或专业评价的词搭配，如 recommended（推荐的）、skilled（熟练的）、regarded（受重视的）；不太用于修饰像 hot（热的）、tired（累的）这类普通形容词。

  Doctors say the new vaccine is highly effective against severe illness.

  医生说这种新疫苗对重症非常有效。

• extremely

  More neutral and widely used in everyday speech; can intensify almost any adjective or adverb, including ones describing weather, feelings, or physical states, without sounding overly formal.

  语气更中性，日常口语中使用广泛；几乎可以加强任何形容词或副词，包括描述天气、情绪或身体状态的词，听起来不会过于正式。

  I was extremely tired after walking for six hours straight.

  连续走了六个小时后，我感到极其疲惫。

Highly and extremely both intensify an adjective or verb, meaning 'very'. Highly is formal and often written, typically paired with words of praise or evaluation, such as 'highly skilled'. Extremely is stronger and everyday, and can modify almost any adjective, especially words describing extreme states.

两者都用来加强形容词或动词的程度，意思接近，但语气和常见搭配不同；highly 偏正式、书面语气，常与表示评价或赞许的词搭配，extremely 语气更强烈、更口语化，可修饰几乎任何形容词，尤其是表示极端状态的词。