A. at the back of B. nice C. pioneer D. position A. radio astronomer B. be born with C. Toronto D. improbable A. festival B. sheet C. super D. can't A. downhill B. stereotype C. false D. dry-clean A. in terms of B. hybrid C. What's worse D. rain A. nature shows B. puzzle C. charity D. pasture A. shoplifting B. surfing C. chemistry D. Olympic Games A. Australia B. pencil-box C. crossword D. likelihood A. doorknob B. simplify C. mice D. based A. ox B. up-to-date C. decision D. thither