通过努力,他们终于成功地完成了这项工程.After ___ hard,they ____ ____ _____ the project at last.

After _working__ hard, they _succeeded in finishing the project at last.
After _working__ hard, they _managed to finish / compelete the project at last.

After (working) hard, they (succeeded) (in) (completing)the project at last.

After (working) hard,they (succeeded) (in) (completing)the project at last.