AMBA 3 APB Protocol document no:ARM IHI 0024B

I have the following doubts in AMBA 3 APB v1.0

1) How the APB slave generate PREADY is high /low? 

2)What are all the factors APB slave have to consider  while generating the PREADY is high /zero? Eg) PSELx, PENABLE, states etc

3) in figure 2-2,During the right transfer with wait states ,PSELx and PENABLE is high PREADY is low for 2 clock period. Why PREADY is low for 2 clock ? (ref Figure 2-2 Write transfer with wait states)

4)how to check the write /read transfer with wait states on simulation ?

5)in access state at what condition PREADY will be low ?