当老国王去世时，他的儿子登上了王位。

When the old king died, his son ascended ___to ___the ___throne.

条约签署时，一位年轻的女王正统治着国家。

When the treaty was signed, a young queen was ___on ___the ___throne.

作为长子，这位王子是王位的直接继承人。

The prince, as the eldest son, is the direct heir ___to ___the ___throne.