A. cross B. mainstream C. insurance D. new A. chief B. skull C. math D. rural A. aerospace B. stack C. their D. What's the matter A. promontory B. hostile C. party D. trolleybus A. competition B. bewilderment C. mutton D. door A. Christmas B. turn around C. ping-pong D. bye A. aftershock B. grass C. sixteen D. lychee A. power line B. down C. beautiful D. lie A. CD B. implication C. in class D. learner A. sword B. how much C. dollar D. workmate