他从2005年起就开始学习中文了.he has started to learn Chinese since 2005.

当然有问题了since加时间点只能用延续性的动词learn的现在完成时态,而不能用瞬时动作的start应该改为he has been learning Chinese since 2005。he has learned Chinese since 2005。he started to leaning Chinese in 2005。