He used a rope to mark off the circle.

他用一根绳子把这个圈围了起来。

《柯林斯英汉双解大词典》

I can't figure out where the middle of my rope is because my rope doesn't have a middle mark.

我认不出我的绳子哪里是中间，因为我的绳子根本就没有中间点记号。

youdao

You will need a marked rope or a 100ft measuring tape to mark out the site, and a foot-wide wooden board about 4ft long to do the flattening.

准备一条有标记的绳子或者是100英尺的卷尺，用来给场地划定界限。准备一个与脚同宽，长约4英尺的木板，用以压倒麦秆。

youdao

Jayawardene was single-handedly holding the innings together and his ability to find the rope with an element of regularity drove Sri Lanka past the 100 mark.

BBC: Sri Lanka see off valiant Ireland