401k可以选么？ 还是问选什么基金？

LZ应该是在问选什么样的基金

it all depends.  what's your risk appetite?  what's your risk tolerance?  what's your goal for short and long term? 

most people start with 80% stock (mix of domestic and international) and 20% bonds.

401k和其它投资的不同地方是60岁的时候钱才能拿出来。lz如果是三十岁，那就是30年以后取钱，所以不是短期投资。investment syle -> high risk high return。因此不建议放在bond里，100%放在stock funds. 如重雪说的，mix of domestic and international. international funds 尤其不能错过。

Every company offers its employee a number of mutual fund choices.  The mutual funds are categorized based on their risk/return. 

You can pick one of two funds within each category, based on the suggestions above.