2006-12-A-21

Conclusion: Any garden and adjoining living room that
are separated from one another by sliding glass
doors can visually merge into a single space.

Premise:If the sliding doors are open, as may happen in
summer, this effect (can visually merge into a single space)will be created if it does not
already exist and intensified if it does .

Premise: The effect  (can visually merge into a single space)remains quite strong during colder months if the
  garden is well coordinated with the room and
contributes strong visual interest of its own.

在红色的三种情况下（3个if)，都会有can visually merge into a single space.

D) even if the garden does not contribute strong visual interest of its own =不是第三个if,

但可以认为是
   第一或第二个if中的一个或两个，这两个都可以推出can visually merge into a single spa

The essence of the stimulus is saying that there are two sets of sufficient conditions爐hat爓ould爉ake a garden adjoining a living room that are separated from one another by sliding glass doors to visually merge into a single space.

The two sufficient conditions are: 1. openning the door in summer; 2. in colder months: a garden is well coordinated with the room and
contributes strong visual interest of its own.

The credited option D boils down to: a necessary condition could occur without its sufficient conditions being met.