Snow fell against the high school all day, wet big-flaked snow that did not stick well. Sharpening two pencils, William looked down on a parking lot that was a blackboard in reverse. Car tires had cut smooth arcs of black into its white, and where the school buses had backed around, there were handsome pairs of "V's". The snow, though at moments it whirled thick and heavy, could not quite bleach these scars away. The temperature must be exactly 32 degrees. The window was open a crack^*. The cedarwood smell of pencil shavings mingled with the musty odor of the wet window sill. With each turn of the handle his knuckles came within a fraction of an inch of the tilted window, and the faint chill that this closeness breathed on them, sharpened his already keen sense of shelter.

^* The following examples are from the web:

• The window was open a crack.
• It was warm out, but not super hot, and the window was open a crack so there couldn't have been some kind of pressure buildup in the car.
• Luckily, the girls were already one step ahead, as the window was open a crack so we can hear what they were saying.

Q. Underline a sentence which supports the answer to question No. 2.