Perhaps you should try some spelling variations:
present challenges » current challenges, assessment challenges
challenges caused » challenges case, challenges chapter, challenges call
la present » la presente, a present, la presence
long chain » long chemin, long grain, long han
long hai » hong hai, long han, long haul
yang xi » yang di, yang yi, yang jui
lng a » lng _, leg a, lpg a
wang » wing, wan, lang

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((wang yanling) or (yang xi))lng a la present challenges caused ((long hai) OR (long chain)) ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((wang yanling) OR (yang xi))lng a la present challenges caused ((long hai) OR (long chain)) ;*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((wang yanling) or (yang xi))lng a la present challenges caused ((long hai) OR (long chain)) ;*".