請問有否犯錯??

Tom proved himself to be a dedicated and sensitive officer. He was assigned as a core member to work with a special project for designing and testing () the pneumatic control system which will be applied in the KFC’s project. The control system must be done in a detail-minded and meticulous approach, in which he evaluated the components to assure compatibility well[註] in advance. He carried out integrated tests for each module and prepared technical reports. After that he co-operated with other staff to roll out the systems. Since those works were complicated in system wiring and lasted for a certain period for reliability testing, execution () () must done by team-work. He evaluated the equipment first to avoid any system mismatch, and then he made a pre-test for each module and updated the program documents. Although failures of testing were frequently, which increased his workload, from these he gained more experience and learned more skills of user-friendly setting. He continued to maintain his strength and productivity, and has made a lot of efforts to increase the quality of products .


2nd last句可以用in spite of frequent failures in testing, he gained ...

註:
to assure compatibility well 很好地保證相容性
well 是指著那個詞? 如果是指 well-compatible, 那麼應寫成 to assure good compatibility 保證良好的相容性.

有些現在式我也改為過去式.

我想問為甚麼有時是system, 有時卻是systems?
我不清楚有多少個system, 唯有在此提醒你留意一下.