@@ -246,7 +246,7 @@ You can have a `variant<>` to accommodate several types of variables provided (i
 template <size_t n, typename... T>
 constexpr std::variant<T...> _tuple_index(const std::tuple<T...>& tpl, size_t i) {
     if constexpr (n >= sizeof...(T))
-        throw std::out_of_range("越界.");
+        throw std::out_of_range("tuple index out of range.");
     if (i == n)
         return std::variant<T...>{ std::in_place_index<n>, std::get<n>(tpl) };
     return _tuple_index<(n < sizeof...(T)-1 ? n+1 : 0)>(tpl, i);