the danger of drunk driving many drivers promised never to drive after drinking.A. Reali

问题补充：

the danger of drunk driving, many drivers promised never to drive after drinking.

A. Realizing

B. To have realized

C. Realized

D. Having realized

答案：

A. Realizing

B. To have realized

C. Realized

(答案→)D. Having realized

解析：根据下文为过去时态,可知前文应为完成时态,意识到醉酒驾驶的危害,许多司机承诺永远不酒后驾车.