The company then spent ten years perfecting the clock before beginning to manufacture it in its current technological form in 1946.

In total, he took six years perfecting the murals which were his last major work.

He had spent years perfecting a body that was a natural marvel.

But it's a contender for favorite festival in a place that has has spent almost 300 years perfecting the art of celebrating.

Here he remained five years, meantime perfecting himself in English.

I, on the other hand, have spent the last twenty years perfecting my ability.

The co-founders spent two years perfecting their concept, focusing particular attention around their original setting.

For example, we know that he spent two years perfecting the attribute of "greeting every individual with a pleasant facial countanence".

He spent a further two years perfecting his technique at Colorado University.

He spent thirty years perfecting the technique before releasing his findings to the general public in the late 1960s.