无法解决的
4.Any production problem (no solution online) should report to EE for resolving.
5.Any production problem (no solution online) should report to PE for resolving.
7.A priori speculation upon questions that are unanswerable to scientific observation, analysis, or experiment.
8.Since there are many intractable problems, the war is likely to break out.
9.The concept is an example of how apparently intractable problems can, and should be resolved.
10.When difficulties cannot be resolved for the time being, we should explain the reasons patiently and honestly.


