31804. 阅读下列程序:Sub Med(x%, ByVal y%)x = 3 * x: y = x + yEnd SubPrivate Sub Form_Click()Dim a%, b%a = 3: b = 8Med a, bPrint a, bEnd Sub运行后,单击窗体,输出结果为( )。(A) 3 8(B) 3 17(C) 9 8(D) 9 17(答案:C) 32009. 用( )语句打开顺序文件File1.txt后,可以进行写操作。(A) Open File1.txt For Input As #1 (B) Open File1.txt For Output As #1(C) Open File1.txt For Random As #1 (D) Open File1.txt For Binary As #1(答案:B)32006. 下列叙述正确的是( )。(A) 一个记录中所包含的各个元素的数据类型必须相同?(B) 随机文件中每个记录的长度必须相同?AB