课文详注 Further notes on the text

1.…he soon changed into the dead man's clothes.
……(他)很快就换上了死者的衣服。

change into 在这里表示“换(衣)”:
He changed into his new dress and went to the party.
他换上新衣服去参加聚会。

2.…the prisoner marched boldly up and down in front of the camp.
……(那战俘)在军营门前大胆地来回走着。

march 一般用于指部队“行军”、“行进”,但在这里它表示“(威风凛凛/从容不迫地)走”或“迅速地走”:
Jane marched out of the room without saying a word.
简一言未发,快步走出了房问。

up and down 为固定词组,其含义之一为“来来回回”:
He was worried about his mother and walked up and down in the room.
他为他母亲担心,便在屋里来回走。

3.men were running here and there
人们在东奔西跑

here and there 为固定短语,表示“到处”、“四处”:
That morning there were policemen here and there.
那天上午到处都有警察。

They went here and there looking for the lost child.
他们到处寻找那个丢失的孩子。

4.…the prisoner stood to attention and saluted as they passed.
……战俘立正站好,并在他们从他面前经过时敬了礼。

attention 在此表示“立正姿势”。单用“Attention!”表示口令“立正!”“立正站着”则用短语 stand at/to attention表示:
The students stood at/to attention while the headmaster made a speech.
校长发表演说时学生们立正站着。