(2013·郑州质量检测)—Jack hurt his leg yesterday.

—Really？________？

A．What’s wrong with him

B．How did it happen

C．Wasn’t he too careless　

D．Who told you that

下述函数统计一个字符串中的单词个数，单词是指处在空格之间的字符序列，请填空。
int word(char*s)
int num=0,flag=0;
while(*s)
if(______=’’) flag=0;
else if(______)flag=1;num++

return______