n. if you make a U-turn when you are driving or cycling, you turn in a half circle in one movement, so that you are then going in the opposite direction. 可数名词 U型转弯，180度转弯，掉头
2. if you describe a change in a politician's policy, plans, or actions as a U-turn, you mean that it is a complete change and that they make the change because they were weak or were wrong. 可数名词 政治家在政策、计划、行动方面的180度大转弯、彻底转变 disapproval（负面色彩）
a complete change of ideas, plans etc
U-turn是可数名词，本意是“掉头，转弯”，可以引申为“改变”。开车时“掉头”的英文是make a U-turn， 所以这个词很好记。U-turn比change更强调改变的彻底性，是一个非常形象、准确的单词。
1. In the past two years, the local government has been utterly inconsistent with its policies, making various U-turns. 过去两年，地方政府的政策完全不一致，出现了各种180度的大转弯。
utterly completely – used especially to emphasize that something is very bad, or that a feeling is very strong 完全地，十足地 用于强调事物糟糕或感情强烈
2. If you want to be a respected leader, you had better avoid making too many U-turns when making decisions.
3. Many critics accuse the European government of doing a sudden U-turn on its promise to take in more immigrants.
4. Earlier this year, AMD forced Intel to make a U-turn in its 64-bit-chip strategy. 今年早些时候，AMD迫使英特尔z在64位芯片战略上做出了180度的大转变。
5. A year later, following the collapse of Lehman Brothers, the markets made a U-turn.
He has made a U-turn and decided to remarry his divorced wife. / He has made a U-turn, deciding to remarry his ex-wife.
Knowing who he was, he made a U-turn and put on a flattering smile.