質問: as soon as my dog started to bark as soon as he heard my voice と my dog started to bark as soon as he had heard my voice のどちらで書いても違いは無いですか? また、この文をno sooner than、hardly when で書き換える時は過去完了形を使わないといけないのでしょうか?
回答: 以下のとおりお答えします。 as soon asを使って書くなら、 my dog started to bark as soon as he heard my voice. と過去形が普通でしょうね。 no sooner thanを使って書き換えるなら、おっしゃるように、 my dog had no sooner heard my voice than he started to bark. と過去完了形を使うことになります。 「私の声を聞くか聞かないうちに」と強調するなら、 no sooner had my dog heard my voice than he started to bark. とにすることになります(語順にご注意)。 hardly when を使う場合も、 my dog had hardly heard my voice when he started to bark. と過去完了形を使わないといけないでしょうね。