The basic physical principles involved in electrostatic fluid acceleration have been understood at least since the industrial revolution.

I've understood since the first visit in August.

This is the first time that John has understood an animal since his childhood.

Although we've understood its usefulness since ancient times, it's taken us until recently to fully understand the danger lead poses to our health.

This much had been understood since the first rays of the first dawn.

But, first, the idea of social betterment as it is understood since the October revolution doesn't fill me with enthusiasm.

Although this was not his planet, Liet had understood the potentially lethal nature of storms since childhood.

I have understood this ever since Jastrow filled in the blanks, as it were.

Pride, she should have understood, since a fierce pride and strength all but shone from her.

This has been understood since the days of Thomas Edison.