题目

Lilly and Audrey are younger than most cookbook authors. But they have been developing their kitchen skills for more than half their lives. When they had just learned to walk, they loved to hang out in the kitchen while their parents cooked dinner. At age 5, they made their first dish without help: pumpkin muffins. Audrey can still remember the way the muffins rose in the oven (烤箱), the painful wait for them to cool and the sweetness of the fresh-made treats. It was super exciting to make something so delicious almost all on our own, she says. Their parents are not very skilled at c是“直线和直线垂直”的(    )A．必要而不充分条件 B．充分而不必要条件C．充要条件D．既不充分也不必要条件