皮皮学，免费搜题
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搜题
【单选题】
肠梗阻患者最重要的非手术措施是A.
禁食、胃肠减压
B.
纠正水电解质失衡
C.
加强营养
D.
腹部按摩
E.
阿托品解痉
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皮皮学刷刷变学霸
举一反三
【单选题】下面关于防病毒软件,正确的是( )。
A.
防病毒软件需要定期升级病毒库
B.
防病毒软件能查杀所有的病毒
C.
防病毒软件不用经常升级照样能够查杀病毒
D.
防病毒软件不升级,就不能查杀病毒
【简答题】若一个n级排列作了奇数次对换后变成了排列123....n,则原来这个排列的逆序数为 。
【单选题】Choose the best way to approach the guest in the following situation. You are asking a guest to wait 15 minutes until his room is ready. You say:
A.
Sir, it will be 15 minutes until your room is ready. Would you like to take a seat, and I will order you a tea or coffee.
B.
You have to wait for 15 minutes.
C.
I'm sorry, Sir. It will be 15 minutes until your room is ready.
【单选题】Choose the best way to approach the guest in the following situation. The guest has a choice of potato to go with his steak. You say:
A.
What would you like? Fries or baked potato?
B.
That comes with either fries or baked potato. Which would you prefer?
C.
You can have fries or baked potato.
【判断题】二阶和三阶行列式每一项前面的符号可以这样定,先把每一项因子中的行下标按自然数排列,然后计算列下标的逆序数,奇排列取负号,偶排列取正号。由此猜测: n阶行列式中每项的符号在行下标为自然排列的前提下,若列下标排列为奇排列,则取负号,否则偶排列取正号。
A.
正确
B.
错误
【简答题】任何排列均可通过施行若干次对换化为标准排列,设排列 的逆序数为 t ,可以通过 m 次对换将其化为标准排列,则 t 与 m 的关系为 _______________ 。
【单选题】What makes the situation of having a conversation with the guest more complicated for the doorman?
A.
Guest names.
B.
Their homeland.
C.
Their social position.
D.
Their different cultures.
【简答题】在m（m≥2）个不同数的排列P 1 P 2 …P n 中，若1≤i＜j≤m时P i ＞P j （即前面某数大于后面某数），则称P i 与P j 构成一个逆序，一个排列的全部逆序的总数称为该排列的逆序数。记排列（n+1）n（n-1）…321的逆序数为a n ，如排列21的逆序数a 1 =1，排列321的逆序数a 3 =6。 （1）求a 4 、a 5 ，并写出a n 的表达式； （2）令 ，证明2n＜...
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