关于空调装置的说法中哪些正确：（）.

A.新鲜空气进风口设在室内

B.进风口不必考虑污染源

C.空调器过滤材料应定期清洗

D.空调器过滤材料不必更换

下列程序的输出结果是______。
#include＜iostream＞
using namespace std;
Class Test
public:
Test()cnt++;
～Test()cnt--;
static int Count()return cnt;
private:
static int cnt;
;
int Test::cnt=0;
int main()

cout＜＜Test::Count()＜＜"";
Test t1,t2;
Test*pT3=new Test;
Test*pT4=new Test;
cout＜＜Test::Count()＜＜"";
delete pT4;
delete pT3;
cout＜＜Test::Count()＜＜end1;
return 0;