高等植物的老叶由于缺少某一种元素而发病，下面元素属于这一类的有（）
A、氮
B、钙
C、铁
参考答案：A
The professor explained this theory so clearly that this phenomenon was easy enough ____. [ ]
A. for us to work out
B. working out
C. for working out
D. to working out
以下程序运行后的输出结果是______。 int d=1； fun(int p) static int d=d; d+=p; printf("%d",d) ;return d; main() int a=3; printf("%d\n",fun(a+fun(d)));
A．699
B．669
C．61515
D．6615
