Usage of Explicit Constructors, while the parameters are passed by reference [duplicate]

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• What does the explicit keyword mean? 11 answers

I have a Class with a constructor taking 2 std::string parameters by reference. In this case, does it make sense to change the constructor into an explicit one?

struct Foo { Foo(std::string& a, std::string& b); };
struct Bar { explicit Bar(std::string& a, std::string& b); };

In the above code, What would be the best thing in Bar from Foo?