goalposts

英 [ˈgəʊlˌpəʊsts]

美 [ˈgoʊlˌpoʊsts]

n. 球门柱
goalpost的复数

柯林斯词典

（足球等运动的）球门柱
Agoalpostis one of the two upright wooden posts that are connected by a crossbar and form the goal in games such as football and rugby.
PHRASE （为一己私利）改变规则
If you accuse someone ofmoving the goalposts, you mean that they have changed the rules in a situation or an activity, in order to gain an advantage for themselves and to make things difficult for other people.
1. They seem to move the goal posts every time I meet the conditions which are required.
  好像每当我达到规定条件时，他们就改变规则。