俱舍論記 9.90

9.90

「有時但說至二分攝故」者，因解三際攝十二支，復明二分攝十二支。前際七中，二因招五果；後際五中，三因招二果。此即因果分為二際。

"Sometimes it only states... because it is subsumed by two divisions": having explained the three time periods subsuming the twelve links, it further clarifies the two divisions subsuming the twelve links. Among the seven of the earlier period, two causes bring about five effects; among the five of the later period, three causes bring about two effects. This divides cause and effect into two periods.