条件・譲歩N2
〜以上（は）
now that... / as long as...
Structure
V-辞書形／た形 + 以上（は）；い形 + 以上（は）；N + である + 以上（は）
Explanation
Expresses "now that one is in a certain state or has done something, one should/must...", stressing the speaker's resolve, obligation or responsibility. Attached to the dictionary/ta/te-iru forms of verbs, or na-adjectives/nouns + である. The main clause often uses 〜なければならない, 〜つもりだ, 〜責任がある.
Examples
約束した以上、必ず守らなければならない。
Now that we've promised, we must keep our word.
日本で働く以上は、日本語をしっかり勉強すべきだ。
As long as you're going to work in Japan, you should study Japanese seriously.
Note
The main clause after 以上(は) must express resolve, obligation or advice, not a plain statement of fact.