  For integers x and k, let T(x;2k) denote the number of twin prime pairs
(p,p+2k) with a distance 2k<=2x**0.5 and p<=x (not p+2k<=x). Let Tg(x;2x**0.5)
denote the average of T(x;2k) for all 2k<=2x**0.5. Logically, T(x;2k) should be
a function of Tg(x;2x**0.5). We first, propose a sliding model to estimate
Tg(x;2x**0.5). Second, derive the relations between T(x;2k) and Tg(x;2x**0.5)
from the sieve structure. Third, settle the errors caused by the dependence of
primes.
