Gangs seem to be an intractable problem.

一伙在看来似乎是一难驾御的问题。

There is no easy fix for an intractable problem.

没有简单的办法解决难题。

The dating of planation surface is still an intractable problem.

而另一方面，夷平面的定年仍是一个棘手的问题。

The most intractable problem of glioma is tumor recurrence after operation.

脑胶质瘤治疗中最棘手的问题是术后肿瘤复发。

Worse than this, discovering the direction of bias may be an intractable problem.

更差的情况是，发现偏向方向可能是难于解决的问题。