I think it has technical problems, and still needs improvement. 我觉得高铁还存在技术问题,仍然需要改进(NI)。
You have a good vocabulary, but your grammar needs improvement. 你的词汇量不小,可语法知识需要提高。
One area where the industry needs improvement is in the life span of its products. 该行业需要改进(NI)的一个领域是其产品的寿命。
Your written English is fairly good, but your spoken English needs improvement. 你的英文文笔还不错,但你的英文口语就需要加强了。
Legislation concerning the responsibility of the network vendor is relatively scattered, which needs improvement with a uniform law. 我国关于网络服务商责任的立法相对分散,需要制定统一的法律予以完善。