In the third, the humans start using signs and develop logic.

Before humans started using fire, eating grains was not a very useful way to get energy.

After all, the first humans started with less than we have.

Wood has been an important, easily available material for construction since humans started building shelters.

One never knew when humans would get religion and start killing.

He was the first, but soon after the war many other super-powered humans started to appear.

The humans started, and one looked about covertly for the speaker.

In series 4, the humans start building a new railway that is planned to be built through the area where the animals live.

The humans and not the aliens, started the war which has been destroying the human race.

At the end of the last ice age, humans started to inhabit the mountain range.