Audio problem: When General Ross is shaking hands with Doc Samson and saying "Welcome aboard. I'll see you at the team briefing in the base hangar, five minutes," his mouth is closed for the first 8 words.
Audio problem: When General Ross interrupts Gabe Jones by saying "Will be under my exclusive command," his mouth is not moving for the word "exclusive."
Audio problem: When General Ross is saying to Major Talbot "If Nick Fury thinks he can just..." his mouth isn't moving.
Other mistake: When the Hulk takes down the S.H.I.E.L.D. helicopter, it is shown crashing to the ground with its pilot parachuting to the ground shortly after. However, the pilot was never seen ejecting and the helicopter's cockpit door was still closed when it crashed to the ground.
Deliberate mistake: As usual when the Hulk reverts back into Bruce Banner, he is left wearing nothing but tattered pants. When Mitch McCutcheon sneaks Bruce Banner into the nuclear research facility, Banner is shown wearing his usual outfit of a gray collared shirt tucked into purple slacks that are intact. Given that the Hulk was just in the middle of the Nevada desert, Bruce Banner would be in no position to have a change of clothes on him, and the idea that the top secret facility would have an exact match of his go-to outfit is ludicrous.
Answer: The Hulk is a giant brute who smashes everything in his path when he is angry. In Ang Lee's "Hulk," General Ross, played by Sam Elliot, explains it to his daughter.