A. human race B. Nile C. careless D. division A. collapse B. amber C. surface D. radioactivity A. I'm B. poet C. thumbs-up D. fill in A. shorts B. Arctic C. Chinese medicine D. get out of A. pronounce B. work out C. slander D. work of art A. safeguard B. foundation C. kiss D. car pool A. erode B. Spanish C. detail D. simple A. healthy B. largely C. sandwich D. rude A. cheek B. main course C. wonder D. winter A. another B. California C. Japan D. break