Construction will begin as soon as we __________

【問題】
Construction will begin as soon as we __________ the necessary building permits.

【選択肢】
1.　are obtaining
http://jibun.atmarkit.co.jp/scenter/ittrain/93_20060929_a1.html

2.　have obtained
http://jibun.atmarkit.co.jp/scenter/ittrain/93_20060929_a2.html

3.　will obtain
http://jibun.atmarkit.co.jp/scenter/ittrain/93_20060929_a3.html

4.　had obtained
http://jibun.atmarkit.co.jp/scenter/ittrain/93_20060929_a4.html

問題提供：リアル・イングリッシュ・ブロードバンド株式会社
http://jibun.atmarkit.co.jp/misc/ct.php?id=TR56_RE1
No.09320060929