Scientific research shows that animals can show emotions like human beings. They are sometimes lively, and sometimes bad-tempered.
A. contradictory
B. instant
C. appropriate
D. flexible
网友回答
A. contradictory
B. instant
C. appropriate
(答案→)D. flexible
解析：考查形容词。A．contradictory矛盾的；B．instant立即的；C．appropriate适当的；D．flexible灵活的。句意：科学研究表明，动物可以显示像人类一样灵活的情感。它们有时活泼，有时坏脾气。故D正确。