为检验回转机械安装或检修质量是否符合标准要求，须经试运行考核。
参考答案：对
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
汽油喷灯加油量一般为容量的（）。
A、30%
B、50%
C、75%
D、100%
