Not dare to "賜教", just a suggestion for your reference.
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It is easy to get the evidence your lawyer wants. You can get help from your current boss. Ask your boss to write a letter to state how many candidates have applied for or showed interest in the postion you are curretly holding, and why your boss chose you not other candiadtes, etc. This letter can serve two purposes 1) there is no labour shortage, 2) you are superior to other candidates, and you will make more contributions potentially to your current work/project which is of national interest.
Good luck.