A. force B. investigate C. twenty-first D. disease A. nationality B. possible C. at the edge D. on air A. course B. mirror C. risk D. yawn A. sugar B. disadvantage C. dubious D. global warming A. dislocate B. surprise C. postcode D. Wednesday A. arrival B. mark out C. without D. just right A. plate B. yield C. promontory D. rambler A. sandwich B. alphabet C. metro D. walk on A. hang out B. overnight C. measure D. cancer A. feed on B. watermelon C. rural D. invite