Is Tom at school today? No, He's at home ______ he has a bad cold. [ ]

A. because

B. if

C. until

D. before

以下程序运行后的输出结果是______。 #include＜stdio.h＞ main(){ 　 int a=200, b=010; 　 printf("%d%d\n", a, b); }