. Scientists have to work hard to keep_____ with modern discoveries and developments.

It is widely known that burning coal for electricity is one of the main causes for global warming , but we can’t ignore the cars’ _____ to the greenhouse effect.

I’m not sure whether we can have a picnic on Saturday evening, because it _________ the weather.

We would appreciate _______ if you could give us some advice on how to solve this problem

_______ makes the book so extraordinary is the creative imagination of the writer