问题如下：
Drawbacks of technical analysis include which of the following?
选项：
A.It identifies changes in trends only after the fact.
B.Deviations from intrinsic value can persist for long periods.
C.It usually requires detailed knowledge of the financial instrument under analysis.
解释：
A is correct.
Trends generally must be in place for some time before they are recognizable. Thus, sometime may be needed for a change in trend to be identified.
老师问下c为啥错了 技术分析不是需要用到一些工具才行吗
