题目

—Where have you been all day?     —I _______ some former classmates and I couldn’t get back until it was dark.    A. have met           B. met               C. would meet     D. had met 答案：B小红每天做a个零件，小强每天比小红多做8个，a+8表示________，5a表示________，5（a+8）表示________．