1·Yet a multiplicity of countries, though it makes river management complicated, does not necessarily add to the intractability of a dispute.
然而，虽然一国多河使河流管理更加复杂，但它不一定使争端更加棘手。
2·One of the intractability appeared in researches is how to restrain all kinds of artifacts quickly and efficiently.
大量研究表明，怎样快速有效地抑制各种原因产生的伪影，仍然是研究人员所面临的一个非常棘手的问题。