Their case shows how personal forces often drive the research enterprise.

Both economic and cultural forces drive the desire for boys, public health officials said.

However, it seems that the forces driving these changes in period are different.

What forces drive the oceans every second of the day?

Another force driving the debate is the growing cost of all this technology.

Three forces drive most human changes - power, wealth and personal impact.

The force of the round drove the Justice man back across the road.

The fundamental forces driving these changes are here to stay.

The force of the water drove him to his knees.

For the first time, she understood what forces drove this woman.