Many of them turned a deaf ear to her advice, _______ they knew it to be valuable.

A．even though

B．now that

C．as if

D．as long as

在烹饪过程中使用香味调料，其结果是菜点的香气大大超过原料固有的香气而形成一种综合香气，使人产生愉快感，增加进食者的食欲。