A. opening B. pony C. efficient D. smoke A. gravitational B. threaten C. Roman D. freestyle A. immigrant B. cynic C. take action D. atmosphere A. balloon B. scraper C. close D. skeleton A. throw away B. put C. faulty D. sweets A. in need of B. indiscriminate C. defence D. century A. revive B. catch a cold C. typewriter D. root A. patch B. something C. sticker D. analyst A. sandwich B. main unit C. spoil D. shuttle A. grass-seed B. sunbathe C. downstream D. invaluable