66.The following SAS program is submitted:
 
  data WORK.SALES; 
     do Year=1 to 5; 
        do Month=1 to 12;
           X + 1;
        end;
     end;
  run;
 
How many observations are written to the WORK.SALES data set? 
 
     A. 0 
     B. 1 
     C. 5 
     D. 60
 
Answer: B
这个为什么就一个!好像是不是缺少了output ,如果加output 是不是就60个!但为什么呢?