Ask question if you don't understand
It often happens in the class - you do not understand one thing, and it seems that you are alone in this group, everyone else has understood the thing, so do not dare to ask - that people laugh! Do you understand how stupid that it is? Everybody laughed at you today, no matter what two days will you remember?
But after asking for understanding, you have learned the thing but for the whole life! So no longer fool, ask questions, learn to know. There is no shame, but not trying to know is a matter of great shame.