A. exotic B. face to face C. walnut D. systematic A. wheelchair B. lower C. mammoth D. convenient A. radio frequency B. occasionally C. architect D. stadium A. parrot B. top C. personal D. reproduce A. heavily B. observatory C. lantern D. free of charge A. forty-six B. current C. hard-working D. glisten A. call up B. bring back C. feature D. tie A. rust B. examination C. ring off D. forever A. amphibious B. amass C. dim D. confine A. vet B. Mercury C. tetrahedron D. pencil sharpener