  When holes move in the background of strong antiferromagnetic correlation,
two effects with different spatial scale emerge, leading to a much reduced
hopping integral with an additional phase factor. An effective Hamiltonian is
then proposed to investigate the underdoped cuprates. We argue that the
pseudogap is the consequence of dressed hole moving in the antiferromagnetic
background and has nothing to do with the superconductivity. The momentum
distributions of the gap are qualitatively consistent with the recent ARPES
measurements both in the pseudogap and superconducting state. Two thermal
qualities are further calculated to justify our model. A two-gap scenario is
concluded to describe the relation between the two gaps.
