・They cannot find the solution to [for] the problem. その問題の解決法が見つからない.

・a problem difficult [easy] of solution 解決が困難な[やさしい]問題.

2a 溶液, 溶剤.

・a strong [weak] solution 濃[希薄]溶液.

・a normal [standard, standardized] solution 規定液[標準溶液].

・a solution of alum [salt] 明礬(_{みょうばん})[食塩]の溶液.

・a solution of salt in [and] water 食塩の水溶液[食塩と水との溶液].

・a nitrate of silver solution 硝酸銀溶液.

b (ゴムタイヤ修理用)ゴム液 (rubber solution).

3 溶かす[溶ける]こと, 溶解 (dissolution, dissolving); 溶解状態 (dissolved state).

・salt in solution 溶解した塩.