1、We must consider any thistle noxious or helpful according to its effects on cultivated crops.
根据野草对耕作作物的影响，我们必须把每种蓟类植物视为有害或有益。

2、It was clear from the cows' coats that there were thistle patches in the field.
从奶牛的毛发上可以看出牧场里有着朝鲜蓟草的地方。