分不太清有效无效，感觉好乱

NO.PZ2018062002000086问题如下 For a technicanalyst who uses past prices anvolume to prefuture prices, what's his assumption about the market efficiency?A.The market is semi-strong-form efficient.B.The market is weak-form inefficient.C.The market is weak-form efficient. B is correct.Baseon the weak-form efficient hypothesis, investors cannot earn abnormreturns trang on the basis of past prices anvolume. So technicanalysts assume thmarkets are weak-form inefficient.考点Efficient CapitMarket AnIts Forms当技术分析可以获得超额收益时说明市场是弱势无效的。 请问这题哪里说了可以获得超额收益啊？

The market is weak-form inefficient. The market is weak-form efficient. B is correct. Baseon the weak-form efficient hypothesis, investors cannot earn abnormreturns trang on the basis of past prices anvolume. So technicanalysts assume thmarkets are weak-form inefficient.请重新审核改题目答案，私以为是weak-form efficient. 改题目意在考察这一类市场有效性比较低，weak一词已经对efficient做出了修饰，望回复。

The market is weak-form inefficient. The market is weak-form efficient. B is correct. Baseon the weak-form efficient hypothesis, investors cannot earn abnormreturns trang on the basis of past prices anvolume. So technicanalysts assume thmarkets are weak-form inefficient. 老师，这道题问的只是他用了价格等手段去判断，并没有说失败，为什么不能是弱有效市场呢？

老师，我有点做题做晕了，到底是efficiency还是inefficiency啊