— When will the 70th anniversary ceremony for our school ________? All the students and teachers are waiting for it.

— Well, in my opinion, at 9 am.[      ]

A. happen  

B. take place

C. break out  

D. occur

下列程序的输出结果是______。
#include＜stdio.h＞
main()
int x=3,y=2,z=1;
if(x＜y)
if (y＜0) z=0;
else z+=1;
printf("%d\n",z);