[误] Though having been ill for years, he is now quite well.

[正] After having been ill for years, he is now quite well.

. Having been ill for years, he is now quite well.

注：though 是连词，只能用于连结两个从句(clause)。句中 having been ill for years，不是一个从句，至多

前面只能用介词 after，或根本什么都不要。