1. In whatever manner or way:
However he did it, it was very clever.
2. To whatever degree or extent:
“have begun, however reluctantly, to acknowledge the legitimacy of some of the concerns”(Christopher Lasch)
3. In what way. Used as an intensive of how :
However did you get here so soon?
4. In spite of that; nevertheless; yet:
The book is expensive; however, it's worth it.
5. On the other hand; by contrast:
The first part was easy; the second, however, took hours.
6. In whatever manner or way:
Dress however you like.
7. Archaic Notwithstanding that; although.
8. Although some grammarians have insisted that however should not be used to begin a sentence, this rule has been ignored by a number of reputable writers.See Usage Note at but, whatever
虽然有些语法学家坚持认为however 不应用在句首， 但有相当一部分知名作家不理会这条规则参见 but， whatever