On 5 September the Sixth Army advanced eastwards from Paris and met the German IV Reserve Corps, which had moved into the area that morning and was stopped short of high ground north of Meaux. Overnight the IV Reserve Corps withdrew to a better position 10 kilometres (6.2 mi) east and French air reconnaissance observed German forces moving north to face the Sixth Army. General Alexander von Kluck the 1st Army commander, ordered the II Corps to move back to the north bank of the Marne, which began a redeployment of all four 1st Army corps to the north bank by 8 September. The swift move to the north bank prevented the Sixth Army from crossing the Ourcq but created a gap between the 1st and 2nd Armies. The BEF advanced from 6–8 September and crossed the Petit Morin and captured bridges over the Marne and established a bridgehead 8 kilometres (5.0 mi) deep. The Fifth Army also advanced into the gap and by 8 September crossed the Petit Morin, which forced Bülow to withdraw the right flank of the 2nd Army. Next day the Fifth Army recrossed the Marne and the German 1st and 2nd armies began to retire as the French Ninth, Fourth and Third armies fought defensive battles with the 3rd Army which was forced to retreat with the 1st and 2nd armies on 9 September.
以下のとおりお答えします。西部戦線で、フランス軍（および英国遠征軍）が国境線付近を防護したことを述べるくだりです。
＞On 5 September the Sixth Army advanced eastwards from Paris and met the German IV Reserve Corps, which had moved into the area that morning and was stopped short of high ground north of Meaux. Overnight the IV Reserve Corps withdrew to a better position 10 kilometres (6.2 mi) east and French air reconnaissance observed German forces moving north to face the Sixth Army.
⇒9月5日、第六方面軍がパリから東方に進軍して、ドイツ第４予備軍団と戦った。軍団はこの地域に移動してきていて、その朝モーの北側高台に一時的に留まっていたのである。第４予備軍団は、夜を徹してより良い陣地を目指して10キロ（6.2マイル）東へ撤退したが、フランスの航空偵察隊はこれを、ドイツ軍隊が北へ移動して第六方面軍に対峙することになると見た。
＞General Alexander von Kluck the 1st Army commander, ordered the II Corps to move back to the north bank of the Marne, which began a redeployment of all four 1st Army corps to the north bank by 8 September. The swift move to the north bank prevented the Sixth Army from crossing the Ourcq but created a gap between the 1st and 2nd Armies. The BEF advanced from 6–8 September and crossed the Petit Morin and captured bridges over the Marne and established a bridgehead* 8 kilometres (5.0 mi) deep.
⇒第1方面軍の指揮官アレキサンダー・フォン・クルック将軍は、第２軍団にマルヌ川の北岸へ戻るよう命じたが、それは9月8日までに第1方面軍所属の全4個軍団が移動するための始まりだった。北岸への素早い移動によって、第六方面軍がウルク川を渡るのを防いだが、第１、第２方面軍の間に間隙ができてしまった。英国遠征軍は、9月6日–8日に進軍してプチ・モラン川を渡り、マルヌ川上の橋梁を占領して8キロ（5.0マイル）にわたる橋頭堡*を設立した。
＊bridgehead「橋頭堡」（きょうとうほ）：渡河・上陸作戦の際、その地点を掩護し、以後の作戦の地歩を得るための拠点。
＞The Fifth Army also advanced into the gap and by 8 September crossed the Petit Morin, which forced Bülow to withdraw the right flank of the 2nd Army. Next day the Fifth Army recrossed the Marne and the German 1st and 2nd armies began to retire as the French Ninth, Fourth and Third armies fought defensive battles with the 3rd Army which was forced to retreat with the 1st and 2nd armies on 9 September.
⇒第五方面軍もまた（敵軍同士の間の）隙間を進軍して、9月8日までにプチ・モラン川を渡った。これによって、ビュローは、第2方面軍の右側面部を撤退させざるを得なくなった。翌日、第五方面軍が再びマルヌ川を渡ると、ドイツ第１、第２方面軍は撤退し始めた。それと並行して、9月9日、フランス第九、第四、第三方面軍が第3方面軍に対して防御戦を仕かけたので、それも第１、第２方面軍とともに撤退を余儀なくされた。
お礼
回答ありがとうございました。