Following the accident, engineers had to пустоDo a lot of пустоsafety tests before the machine could be used again.
After a long period of failure, they пустоMade an important пустоbreakthrough .
They пустоFound an imaginative пустоsolution to the problem after working with models in the test lab.
One part of the engineering process is to пустоBuild a smaller working пустоmodel before moving on to a full-size or production version.
It can take a long time to fully пустоtheory a complicated пустоTest before putting it into practice.
In the end we were able to пустоSolve the most serious пустоproblem .
On many engineering projects there is great pressure to пустоMeet strict пустоdeadlines .