【简答题】设集合【图片】上的偏序集的哈斯图如图所示,那么偏序集中的关系R是:_____.【图片】用汉字回答
【简答题】直流电机转子 是指电机的哪些结构?又称之为什么?
【简答题】How do you recommend the most suitable souvenirs that tourists can take home as a remembrance?
【判断题】直流电动机的转子与交流电动机的转子结构相同。
【简答题】Every day a number of tourists take pictures in front of the tower, which dates ________ as early as 800 years ago.
【单选题】设集合A={1,2,3,4,5}上偏序关系的哈斯图如下图所示,则子集B={2,3,4}的最大元( );最小元( );极大元( );极小元( );上界( );上确界( );下界( );下确界( )。【图片】
A.
无, 4 , 2 、 3 , 4 , 1 , 1 , 4 , 4
B.
无, 4 、 5 , 2 、 3 , 4 、 5 , 1 , 1 , 4 , 4
C.
无, 4 , 2 、 3 , 4 、 5 , 1 , 1 , 4 , 4
D.
无, 4 , 2 、 3 , 4 , 1 , 1 , 4 , 无
【单选题】According to the passage, who take part in the festival?
A.
Tourists as well as the people around the village.
B.
Tourists and their families.
C.
The mayor and the villagers.
D.
The grandparents and their children.
【单选题】—What should tourists _____ then? —Heavy coat. [ ]