摘要： In my opinion. life in the twenty-first century is much easier than . A.that used to be B.it is used to C.it was used to D.it used to be 答案 D 解析 表示“过去常常-- 用used to do--.并且本题中动词原形be不能省略.

网址：http://m.1010jiajiao.com/timu_id_3872525[举报]