#include<stdio.h>
int a[131072];
int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
    {
        int n;
        scanf("%d",&n);
        for(int i=1;i<=n;i++)
        {
            scanf("%d",&a[i]);
        }
        int ans=(long long)(a[1]+a[n])*250000002%1000000007;
        printf("%d\n",ans);
    }
    return 0;
}