problematic
(also problematical) adj
1 difficult to deal with or to understand 难处理的; 难了解的; 成问题的; 疑难的.
2 (esp of a result) that cannot be foreseen; doubtful or questionable (尤指结果)难以预料的; 有疑问的; 令人不解的.
After switching on powerful arc lights, they saw great stalagmites -- some of them over forty feet high -- rising up like tree-trunks to meet the stalactites suspended from the roof.