下列动物行为不属于防御行为的是 [ ]
A．乌贼遇敌喷墨
B．黄鼠狼遇敌放臭气
C．壁虎遇敌自断尾巴
D．蝴蝶交尾
答案：D
Any student,who is thougnt ______ the rules, for example, by cheating, has _____ before a student court.
A．to have broken; to appear
B．to break; to get
C．broken; taken
D．to break; to be taken
脐带中的血管有
A．5根B．4根C．3根D．2根E．1根
