___ the _____ of modern industry, thepollution is becoming more and more serious.

Edwards’s always chasing after rainbows and never ____ a really practical idea.

You look very happy, why—I have got _______ “A” in the math test.

Sam _____ some knowledge of the computer just by watching others working on it. [ ]

The majority of new businesses fail because,_________ they have a product or service that fills a gap in the market, they usually lack the skills in sales, marketing, and administration.