A. virtue B. specimen C. certainty D. impolite A. classmate B. physicist C. facilitate D. thank you A. sidewalk B. child C. abject D. disunited A. pile B. penholder C. polluted D. debtor A. mainly B. day and night C. nursery rhyme D. obligation A. confusion B. great-grandpa C. impersonal D. trumpet A. blizzard B. oppress C. equip D. be responsible for A. justification B. opaque C. same as D. strange A. assistance B. alien C. creditor D. variation A. cash B. definitely C. friendship D. come round