His mother and Sandy knew the signs of too much concentrated work.

This he did, then for two days young Swift plunged into concentrated work.

Each paid $4,000 to $5,000 for him to prepare a patent application, a process that took more than 40 hours of concentrated work.

Serious, concentrated work, and what was going to happen?

This was a delicate process, requiring many minutes of concentrated work.

After lunch she had a couple of classes, so I had a chance to get some concentrated work done.

It would, however, take several months of concentrated work for him to earn enough money.

The job had still taken more than eighteen hours of concentrated work.

More to the point are his observations of her capacity for sustained, concentrated work.

And the soft water was refreshing after the concentrated work of the day.