33.----How long have you been in this office? ----Just a few minutes. My cousins_______here together with me. A.have walked B.had walked C.walked D.have been walking 答案:C 解析: 本题主要考查动词时态交际中的应用。根据here together with me 可知,是表弟来的行为发生在过去某一时间,因此本题的正确答案选C。m=n+1(m,n为非0自然数),m和n的最大公因数是(________),m和n的放小公倍数是(______)。