"2) EE has a four Pins Mosfet,( D G S B) , Do you think we should make the (B S) connect together? Maybe most of user will left the B float." The 4 pin MOSFET with a Substrate connection is almost always used for monolithic MOSFETs in IC design. I don't think there are any models/subcircuits that use them for discrete devices. It may be best to just remove them or at least hide them from users until someone asks about using EE for IC design! *There are some 4 or 5 terminal MOSFET subcircuits for discrete devices but (usually) they are used for thermal modelling in power devices. They have extra parts of the subcircuit that model the effect of self heating and even allow connection to a heatsink model. I am still learning how to use those models. Fairchild do them but I think other vendors do too.*