题目：The incidence of this disease has been greatly reduced thanks to our health care program.A
The incidence of this disease has been greatly reduced thanks to our health care program.
A．seriousness
B．frequency of occurrence
C．mortality
D．cure rate
空格处的意思是：这种疾病的发病率大大减少要感谢我们的医疗保健项目。划线单词incidence的意思是“发生(率)；影响；影响的方式”。各选项的意思是：seriousness“严肃，认真”；frequency of occurrence“发生频率”；mortality“死亡率”；cure rate“治愈率”。
