The CDC doesn't monitor seasonal flu deaths as closely as it does swine flu, and has no comprehensive count of each year's flu deaths to enable such a comparison.
CDC没能像猪流感那样去监测季节流感死亡，每年能够用于比较的流感死亡数字没有综合统计。
2
The circuit uses IC4, a CD4069 inverter, as a reset-delay enable to cause a few milliseconds of delay before each counter can begin to count.
电路使用IC4的CD4069反相器作为复位延时使能，在每个计数器开始计数前引入几毫秒的延时。
3
Suppose that Enable is high, the counter counts up every clock cycle, and the frequency of the PWM output is the clock frequency divided by 2 count bits.