怎样在集体中表现更为积极活跃

Take the lead in the conversation if it's not going your way
控制谈话的方向，如果它偏离了你的轨道

Often I'll be quiet because the people I'm with are discussing something where I have zero to add, usually because I know nothing about the topic. If that goes on too long, then I'm suddenly the quiet one. If the conversation isn't going your way, try to take the lead and switch it to an area where you'll naturally have more to talk about.
经常，我保持沉默是因为同处的人们正在讨论我觉得无话可说的东西，这往往因为我对这个话题一无所知。如果这持续得太久了，我就突兀地成了沉闷的人。如果谈话没在你的轨道上，尝试引导和切换到一个领域，你自然会有更多的话要说。

More generally, if the other people are talking among themselves, and aren't making an effort in include you, you should take the initiative and try to work your way in there. There's no rule that says you politely have to wait for someone to directly address you and ask your opinion on something.
更一般地，如果其他人在彼此说话，却不打算把你包括在内的时候，你应该采取主动，努力把自己放进去。并没有规定说，你必须礼貌地等待，直到有人来点你的名问你对某事的意见。

Sometimes you just can't come up with something to say
有时，你就是无话可说了

These tips continue to help me, but at times my mind draws a blank. When you can't think of something to say, it's often due to shyness and inhibition interfering with your ability to think freely, and reducing these feelings is easier said than done.
这些小贴士一直在帮助我，然而有时我的大脑仍旧会一片空白。当你无话可说，它往往是由于羞涩和压抑感干扰了你自由地思考，而避免这些情感说起来容易做起来难。

The other usual explanation is when you honestly have nothing to contribute to the conversation (e.g., everyone is talking about old friends they have in common), and it's not appropriate to try and suddenly change it. But here everyone should at least understand that you can't be expected to be too chatty. Try to say something though when the topic changes.
其他常见的解释是：你确确实实拿不出能为谈话作出贡献的东西（例如，大家伙在谈论他们所共有的老朋友），而这时试图突然岔开话题又是不合适的。可是在这种情况下，每一个人至少都明白，不能期望你有太多话可说。所以，一旦话题变化，就试着说些什么吧。

If you do come off as quiet, do better next time
如果你被人看成是沉默的人，下次做好些就行

It's not unusual for someone to be a little tongue-tied around a new group of people. If you do better next time, then people will often forget their first impression of you. They'll realize you aren't a snob after all, or that you aren't meek and boring, and that you're actually a pretty interesting person to have around.
在一群新认识的人面前就好像被绑住了舌头，这样的事并不少见。如果你下次做得更好些，那么人们通常会忘记对你的第一印象。他们会知道你不是势利小人，也不是索然无味之辈，事实上，你真的是个很有趣的人。