#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <cfloat>
#include <ctime>
#include <cassert>
#include <map>
#include <utility>
#include <set>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <numeric>
#include <list>
#include <iomanip>
#include <fstream>
#include <bitset>
   
using namespace std;
   
 
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define foreach(it, c) for (__typeof__((c).begin()) it=(c).begin(); it != (c).end(); ++it)
#define rforeach(it, c) for (__typeof__((c).rbegin()) it=(c).rbegin(); it != (c).rend(); ++it)
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define CL(arr, val) memset(arr, val, sizeof(arr))
#define COPY(dest, src) memcpy(dest, src, sizeof(dest))
#define ten(n) ((long long)(1e##n))
#define bin(n) (1ull << (n))
#define erep(i, n) for (int i = 0; i <= (int)(n); ++i)
#define revrep(i, n) for (int i = (n); i >= 0; --i)
#define pb push_back

template <class T> void chmax(T& a, const T& b) { a = max(a, b); }
template <class T> void chmin(T& a, const T& b) { a = min(a, b); }

template <class T> T round_up(T a, T b) { return (a + b - 1) / b; }

template <class T> void uniq(vector<T>& c) { sort(c.begin(), c.end()); c.erase(unique(c.begin(), c.end()), c.end()); }
 
template <class T> string to_s(const T& a) { ostringstream os; os << a; return os.str(); }
template <class T> T to_T(const string& s) { istringstream is(s); T res; is >> res; return res; }
  
template <class T, class U> ostream& operator<<(ostream& os, pair<T, U>& p) { os << "( " << p.first << ", " << p.second << " )"; return os; }
  
template <class T> void print(T a, int n, const string& deli = " ", int br = 1) { for (int i = 0; i < n; ++i) { cout << a[i]; if (i + 1 != n) cout << deli; } while (br--) cout << endl; }
template <class T> void print(const T& c, const string& deli = " ", int br = 1) { foreach (it, c) { cout << *it; if (++it != c.end()) cout << deli;--it; } while (br--) cout << endl; }
template <class T> void print2d(T a, int w, int h, int width = -1, int br = 1) { for (int i = 0; i < h; ++i) { for (int j = 0; j < w; ++j) {    if (width != -1) cout.width(width); cout << a[i][j] << ' '; } cout << endl; } while (br--) cout << endl; }
   
template <class T> void input(T& a, int n) { for (int i = 0; i < n; ++i) cin >> a[i]; }
template <class T> void input(T* a, int n) { for (int i = 0; i < n; ++i) cin >> a[i]; }

void fix_pre(int n) { cout.setf(ios::fixed, ios::floatfield); cout.precision(10); }
void fast_io() { cin.tie(0); ios::sync_with_stdio(false); }
#define trace(x) (cout << #x << ": " << (x) << endl)
 
bool in_rect(int x, int y, int w, int h) { return 0 <= x && x < w && 0 <= y && y < h; }


typedef long long ll;
typedef pair<int, int> pint;
 
// y(v): v>^<  y(^): ^>v<
const int dx[] = { 0, 1, 0, -1 };
const int dy[] = { 1, 0, -1, 0 };

const double PI = acos(-1.0);

#define F first
#define S second


bool topo_dfs(int v, const vector<vector<int> >& g, vector<int>& color, vector<int>& order)
{
    color[v] = 1;
    for (int i = 0; i < (int)g[v].size(); ++i)
    {
        int to = g[v][i];
        if (color[to] == 2)
            continue;
        else if (color[to] == 1)
            return false;
        else if (!topo_dfs(to, g, color, order))
            return false;
    }
    color[v] = 2;

    order.push_back(v);
    return true;
}
// O(V + E)
// impossible -> return empty vector
vector<int> topological_sort(const vector<vector<int> >& g)
{
    const int n = g.size();

    vector<int> color(n);
    vector<int> order;

    for (int i = 0; i < n; ++i)
        if (color[i] == 0 && !topo_dfs(i, g, color, order))
            return vector<int>();
    reverse(all(order));
    return order;
}

int main()
{
    int n, m;
    scanf("%d%d", &n, &m);

    static vector<pint> g[ten(5)];
    rep(i, m)
    {
        int u, v, w;
        scanf("%d%d%d", &u, &v, &w);
        --u, --v;
        g[u].pb(pint(v, w));
        g[v].pb(pint(u, w));
    }

    int a, b, Q;
    scanf("%d%d%d", &a, &b, &Q);
    --a, --b;

    // 最短経路グラフを作るためにdijkstraします
    static vector<int> prev[ten(5)];
    int dis[ten(5)];
    {
        const int inf = ten(9);
        priority_queue<pint, vector<pint>, greater<pint> > q;

        fill_n(dis, n, inf);
        dis[a] = 0;
        q.push(pint(0, a));
        while (!q.empty())
        {
            int cost = q.top().first;
            int v = q.top().second;
            q.pop();

            if (cost > dis[v])
                continue;

            rep(i, g[v].size())
            {
                int to = g[v][i].first;
                int ncost = cost + g[v][i].second;
                if (ncost < dis[to])
                {
                    dis[to] = ncost;
                    q.push(pint(ncost, to));

                    prev[to].clear();
                }

                if (ncost == dis[to])
                    prev[to].pb(v);
            }
        }
    }


    // 最短経路グラフを作ります
    vector<vector<int> > min_g(n);
    {
        queue<int> q;
        static bool visit[ten(5)];
        fill_n(visit, n, false);

        visit[b] = true;
        q.push(b);
        while (!q.empty())
        {
            int v = q.front();
            q.pop();

            rep(i, prev[v].size())
            {
                int pre = prev[v][i];

                min_g[pre].pb(v);

                if (!visit[pre])
                {
                    visit[pre] = true;
                    q.push(pre);
                }
            }
        }
    }

    vector<int> order = topological_sort(min_g);
    assert(!order.empty());

    // O((Q / 64) * (V + E))
    while (Q > 0)
    {
        typedef unsigned long long ull;

        // 64クエリ or クエリがなくなるまで先読みします
        vector<int> c, d;
        while (c.size() < 64 && Q > 0)
        {
            --Q;
            int cc, dd;
            scanf("%d%d", &cc, &dd);
            --cc, --dd;
            c.pb(cc), d.pb(dd);
        }

        // dp[v]のi bit目が立っている時，c[i] -> vは最短経路上で到達可能
        static ull dp[ten(5)];
        fill_n(dp, n, 0);
        rep(i, c.size())
            dp[c[i]] |= bin(i);

        rep(i, order.size())
        {
            int v = order[i];
            rep(j, min_g[v].size())
                dp[min_g[v][j]] |= dp[v];
        }

        rep(i, c.size())
            puts((dp[d[i]] >> i & 1) ? "Yes" : "No");
    }
}

Measured memory_bytes: 28192