He insisted that his decision to impose restrictions had saved lives and he believed he done a great job.
译为：他坚持说，他实施限制的决定挽救了生命，他相信自己做得很好。
do a great job 固定搭配，“做得好，干得好”的意思，主语为过去式，所以从句也为过去式，省略had ， He believed he (had) done a great job
