【单选题】【消耗次数:1】
The Chinese ( ) paper for two thousand years.
have made
have been making
had made
are being made
参考答案:
复制
纠错
相关题目
【单选题】 I have made _______ dumplings. Now Im making the _______ one.
①  twenty; twentieth-first
②  twenty; twenty-first
③  twentieth; twenty-first
④  twenty; twenty-one
【判断题】 The past 22 years have really been amazing, and every prediction we’ve made about improvements have al come __true__
①  正确
②  错误
【判断题】 判断线上的内容是否正确:The past 22 years have really been amazing, and every prediction we’ve made about improvements have al come __true__
①  正确
②  错误
【单选题】 You have made a ( ) for 8 twins and 4 singles.
①  reserving
②  reserve
③  reserved
④  reservation
【单选题】 20. Only when he had handed in his exam paper ____ he had made several mistakes.
①  he has realized
②  does he realize
③  has he realized
④  did he realize
【单选题】 You can not see the doctor ____ you have made an appointment with him.?
①  except ?
②  even ?
③  unless ?
④  however?
【单选题】 Paper_______by Chinese for thousands of years now.
①  has made
②  has been made
③  was made
【单选题】 She didn’ t come to the party last Sunday._____, she must have made the party more exciting.
①  If she came
②  Would she come
③  Had she come Did she come
【单选题】 She had made many ( ) into the quality of the computer before buying one.
①  inquiry
②  inquiries
③  search
④  research
【单选题】 It was the training that he had as a young man ____made him such a good engineer.
①  that
②  has
③  what
④  later
随机题目
【判断题】 周转轮系的传动比等于各对齿轮传动比的连乘积。()
①  正确
②  错误
【单选题】 带传动不能保证准确的传动比,其原因是______。
①  带容易变形和磨损
②  带在带轮上出现打滑
③  带传动工作时发生弹性滑动
④  带的弹性变形不符合虎克定律
【单选题】 标准直齿圆柱齿轮不根切的最小齿数是____________。  
①  20  
②  17  
③  23  
④  30
【单选题】 凸轮机构中,基圆半径是指凸轮转动中心到______半径。
①  理论轮廓线上的最大
②  实际轮廓线上的最大
③  实际轮廓线上的最小
④  理论轮廓线上的最小
【单选题】 在正常条件下,滚动轴承的主要失效形式为______。
①  滚动体碎裂
②  滚动体与套圈间发生胶合
③  滚道磨损  
④  滚动体与滚道的工作表面疲劳点蚀
【单选题】 键联接主要用于______。
①  传递拉力
②  传递横向力
③  传递弯矩
④  传递扭矩
【单选题】 设计齿轮时,若发现重合度小于1,则修改设计时应______。
①  加大模数
②  增加齿数
③  加大中心距
④  增大压力角
【单选题】 我国标准规定分度圆上齿廓的压力角α=______。  
①  10°  
②  0°  
③  20°  
④  15°
【单选题】 用于联接的螺纹牙型为三角形,这是因为三角形螺纹______。
①  牙根强度高,自锁性能好
②  传动效率高
③  防震性能好
④  自锁性能差
【单选题】 工作时既承受弯矩又传递转矩的轴称为______。
①  心轴
②  转轴
③  传动轴
④  不确定