people / When / come / home .... they / something / have / to eat.

in water / you / When / throw / a piece of wood ... it / floats.

When / put fire to / you / dried grass ... burns / it.

you / When / jump out of / the window ... you / die.

you / When / stop eating ... die / you.

are / You / thristy ... when / nothing / you / have / to drink.

When / see / David / you ... him / tell / I'm running / late / today.

there's / When / a blackout ... can't / you / use / your TV.

there's / nobody / outside / When ... no one / can / the children / watch.

through an area / a river / When / stops / flowing .... the plant life / disappears / quickly.