I wouldn't follow koho-koho suggestion about just nodding. If I were your supervisor and you only nod to what I say, I would have a poor first impression about yourself. Be proactive and initiate opportunities to learn stuff.

There is some truth to what gone12 said about pretending to self about knowing it all. Fake confidence can lead to right confidence; just be aware that you are there to soak in as much as you can so don't hesitate to ask and be adaptive.

Agree about momo advice (Gorkhe); anything that stinks (like indian curry and stuff) is a nono. Just take a simple plain sandwich as a backup incase your group doesn't eat out.