presentation

i have a special presentation yesterday,is the first time have this presentation also..is about parasite,i need to perform how the parasite goes into our body. we need to perform difference kind of character got patient,doctor,parasite,and water seller n lab technician. i feel so nervous, my sound was trembling when i presenting. after all group finish present,my lecturer say tomorrow lab will change to 10am but i didn't hear it,becoz when she talking tat time the class very noisy i cannot hear it..so another i come at 12pm, the class already finish so i n 7 people look the slide by our self.