单选题 Eating better and eating less could be the ______ not only to avoiding cancer but also to living longer.

【正确答案】 A

【答案解析】[解析] key to表示“……的关键”，前面可加冠词the。本句意思为：吃好吃少可能不只是避免癌症的关键，更是长寿的关键。