By the time the courier finally arrived, we

【問題】
By the time the courier finally arrived, we ___________ the package by an alternative carrier.

【選択肢】
1.　have already sent
http://jibun.atmarkit.co.jp/scenter/ittrain/93_20070817_a1.html

2.　had already sent
http://jibun.atmarkit.co.jp/scenter/ittrain/93_20070817_a2.html

3.　already sent
http://jibun.atmarkit.co.jp/scenter/ittrain/93_20070817_a3.html

4.　having already sent
http://jibun.atmarkit.co.jp/scenter/ittrain/93_20070817_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.09320070817