【正确答案】 C

【答案解析】[解析] 该句含义是“许多人抱怨现代生活的快节奏”。rate速度；比率。如：the rate at which hair grows头发生长的速度；Since 1976，the world has been warming at a rate of 2℃a century．1976年以来，世界气候以每世纪增高2摄氏度的速度在变暖。speed速度。如：The police are advising motorists to reduce speed because of the fog. 由于有雾，警察告诫驾车者减慢速度。pace步子，节奏，最符合题意。如：Pay rise fails to keep pace with inflation. 工资的增幅赶不上通货膨胀。density密度。如：the density of air空气密度。