substitute
surface
observation
gather
volcano
incredibly
satellite
ecologically
exactly
wave
They put a weather_______into orbit round the earth.
That's _______- the phrase I was looking for.
Honey can_______ for sugar in this recipe.
Our first task is to _______ information.
A ____ is a disturbance that moves energy form one place to another.
Most of the earth's _____ is covered by sea.
The _______ has been inactive for 50 years.
The survey was based on direct _______ of over 500 schools.
Poisoning the earth's atmosphere is ________ and morally unjustifiable.
They just sounded________romantic.