1 (formal 正式) (used for adding a comment to what you have just said) although sth is true （用于补充刚说过的话）可是，然而: Sales are poor this month. There may, however, be an increase before Christmas. 这个月的销售量很不理想。不过，圣诞节之前也许会增长。

2 (used in questions for expressing surprise) in what way; how （用于疑问句，表示惊奇）到底以什么方式，究竟怎样: However did you manage to find me here? 你到底怎么知道我在这儿？ ☞ When you use only how in a question like this there is not such a feeling of surprise. 这类问句要是只用how，惊奇的语气就会减弱。

3 in whatever way 不管用什么方式或方法: However I sat I couldn't get comfortable. 我怎么坐也不舒服。You can dress however you like. 你爱穿什么就穿什么。

4 (before an adjective or adverb 用于形容词或副词前) to whatever degree 不管什么程度: He won't wear a hat however cold it is. 不管天气怎么冷，他也不戴帽子。You can't catch her however fast you run. 你跑得多快也追不上她。