A. user-friendly B. ambition C. unexplained D. sensation A. Christmas B. at times C. rambler D. physicist A. competence B. regular C. porcupine D. variant A. navigation B. methane C. Houston Rockets D. everywhere A. rugged B. quail C. inform D. overnight A. in the end B. principle C. style D. hover-train A. generation B. reputable C. hovercraft D. rapture A. cotton B. tableland C. favorite D. the United States A. turn around B. until C. sounding D. help oneself A. the Lantern Festival B. wheelbarrow C. random D. dredge