求大神看一下程序

为什8引脚输出的蜂鸣器得不了电
#include <Servo.h>
Servo myservo1;
int pos1 = 60;
int Sensor = 4;
int ina = 9;
const int TrigPin = 2;
const int EchoPin = 3;
float cm;
void setup() {
myservo1.attach(9);
pinMode(ina, OUTPUT); // 9引脚定义为输出
Serial.begin(9600); //设置下载程序的串口的波特率为9600
pinMode(Sensor, INPUT); //4引脚定义为输入
pinMode(TrigPin, OUTPUT);
pinMode(EchoPin, INPUT);
pinMode(8,OUTPUT);
}
void loop() {
int SensorState = digitalRead(Sensor);//读取4引脚的电平
while(SensorState == 1){
SensorState = digitalRead(Sensor); //4引脚为高电平时，设置9引脚为高
digitalWrite(ina,HIGH);
myservo1.write(pos1);
delay(1000); //延时1000ms
}
while(SensorState == 0){ //当4引脚为低电平时，设置9引脚为低
SensorState = digitalRead(Sensor);
digitalWrite(ina,LOW);
}
delay(100); //延时100ms
digitalWrite(8, LOW);
digitalWrite(TrigPin, LOW); //低电平发一个短时间脉冲
delayMicroseconds(10);
digitalWrite(TrigPin, HIGH);
delayMicroseconds(10);
digitalWrite(TrigPin, LOW);
cm = pulseIn(EchoPin, HIGH) / 58.0; //将回波时间换算成cm
cm = (int(cm * 100.0)) / 100.0; //保留两位小数
if (cm>=2 && cm<=10)
digitalWrite(8, HIGH);
}