#include<bits/stdc++.h>
using namespace std;
int a[15];
const int P=1e9+7;
const int two=500000004;
int Pow(int a,int b){
    int ret=1;
    for (;b;b>>=1,a=1ll*a*a%P)
        if (b&1) ret=1ll*ret*a%P;
    return ret;
}
int main(){
    int T=10; scanf("%d",&T);
    while (T--){
        int n; scanf("%d",&n);
        int total=0;
        for (int i=1;i<=n;i++)
            scanf("%d",&a[i]),total+=a[i]/2;
        for (int i=1;i<n;i++){
            int p=(two+1ll*a[i]*Pow(2*a[i+1],P-2))%P;
            total-=1ll*p*(a[i+1]/2)%P;
            //total-=1ll*a[i+1]/2*two%P;
            if (total<0) total+=P;
        }
        printf("%d\n",total);
    }
}