What is the contra positive of the relation represented in the exhibit shown below?

A．R= {<1,2>,< 1,3>,<1,4>,<1,5>}

B．R= {< 1,1>,<2,2>,<3,3>,<4,4>,<5,5>}

C．R= {<2,1 >,<4,1>,<2,2>,<1,3>,<3,2>,<1,4>,<4,4>,<5,4>}

D．R= {<1,2>,<3,1>,<1,4>,<2,2>,<2,3>,<4,1>,<4,4>,<4,5>}

[单选题]What is the most important product-related factor the transport cost? （）A . LinkagesB . DistancesC . EquipmentD . Time

[单选题]What effect does excessive positive ions have on some people?A．They think they are mad.B．They feel very tired.C．They become violently sick.D．They are too tired to do anything.

[单选题] Which of the following statement related to PMO is not correct? (71)(71)A． The specific form, function, and structure of a PMO is dependent upon the needs of the organization that it supports.B． One of the key features of a PMO is managing shared re

[试题]In January 2008 Arti entered in a contractual agreement with Bee Ltd to write a study manual for an international accountancy body’s award. The manual was to cover the period from September 2008 till June 2009, and it was a term of the contract that t

[名词解释] 被动体位（positive position）

[单选题]Although the（ ）is a carrier in his relationship withthe actual shipper， he

[单选题]Although the（ ）is a carrier in his relationship withthe actual shipper， he

[单选题]The book fair has received a positive __ from readers.A． resultB． responseC． settlementD． solution

[单选题]Text 3 The provision of positive incentives to work in the new society will not be an easy task. But the most difficult task of all is to devise the ultimate and final sanction to replace the ultimate sanction of hunger—the economic whip of the old d

[单选题]Positive displacement, helical gear pumps are well suited for pumping oil becauseA．stuffing boxes eliminate the leakage problems usually associated with other gear pumpsB．it is not necessary to closely maintain design clearances with this pumpC．they