问题：
[单选题]设集合A={a,b,c,d},现有A上的二元关系R={<a,b>,<b,c>,<c,b>,<b,a>},则A是( )。
A、自反的
B、对称的
C、反对称的
D、传递的
参考答案：
B
相关内容
- ● If a boy or a girl ha grown up in a home with haring tak and deciion，he or he will probably______.
- ● When a veel ee the other ahead or nearly ahead，by night he could ee the mathead light of the other in a line or nearly in a line or both ide light，（）hall be deemed to exit.
- ● 已知A=40；B=30；C=100；D=50，逻辑“与”运算符为and，“或”运算符为or，“非”运算符为not。计算表达式（A>B+20）or（B+60
- ● 设a=5，b=4，c=3，d=2，则表达式3＞2*b Or a=c And b＜＞c Or c＞d的值是
- ● 设a=5，b=4，c=3，d=2，则表达式3＞2*b Or a=c And b＜＞c Or c＞d的值是
- ● The Urgency Signal（）indicate that the tation calling ha a very urgent meage to tranmit concerning the afety of a hip or aircraft，or of ome peron on board or within ight.
- ● （）mean any peron by whom or in whoe name or on whoe behalf a contract of carriage of good by ea ha been concluded with a carrier，or any peron by whom or in whoe name or on whoe behalf the good are actually delivered to the carrier in relation to the contract of carriage of good by ea.
- ● If he i a common carrier，he i abolutely reponible to the owner of the good carried （）any lo or damage to them unle caued by an Act of God or the Queen’ enemie，or the inherent vice in the good themelve，or the negligence of the owner of the good，or a general average acrifice.
- ● 设a=2，b=3，c=4，d=5，表达式3>2*b or a=c and bc or c>d的值是( )
- ● 设a=5，b=4，c=3，d=2，则表达式3＞2术b Or a=c And b＜＞c Or c＞d的值是
- ● 设a=5，b=4，c=3，d=2，下列表达式的值是 3＞2*b Or a=c And b＜＞C Or c＞d
- ● 设a=5,b=4,c=3,d=2,则表达式3>2*b Or a=c And bc Or c>d的值是
