View Compilation Error

0_0_20485994_4916\Main.java:1: 错误: 需要class, interface或enum
using System;
^
0_0_20485994_4916\Main.java:2: 错误: 需要class, interface或enum
using System.Collections.Generic;
^
0_0_20485994_4916\Main.java:4: 错误: 需要class, interface或enum
namespace a1
^
0_0_20485994_4916\Main.java:31: 错误: 需要class, interface或enum
}
^
4 个错误