题型:单项选择题 ITU-TG.841建议对复用段倒换环的倒换时间作出这样的规定:环上如无额外业务,无预先的桥接请求,且光纤长度少于1200km,则倒换时间应少于()ms。A、20B、30C、40D、50 查看答案
题型:单项选择题 "How dark your brother's hair is!""It's ________ mine when I was at his age."A.no darker thanB.no more darker asC.not dark more thanD.not darker as ~ 查看答案