为什么编译器对std :: vector <std :: string＆>不满意

Question

编译器对std::vector<std::string&>

不满意

而且我不明白为什么这是非法的

#include <vector>
#include <iostream>

std::string makeSetence(std::vector<std::string&> v) {
    std::string result;
    for (int i = 0; i < v.size(); i++) {
        auto w = v.at(i);

        result += w;

        if (i == v.size() - 1) {
            continue;
        }
        result += " ";
    }

    return result;
}

int main() {
    std::vector<std::string&> v;
    std::string test1 = "hello";
    v.push_back(test1);
    std::cout << makeSetence(v) << std::endl;
    return 0;
}