(1)反应(action，feeling or attitude aroused by sth)[C，U][N(to)]：What was the critic's～to the book? 评论家对那本书的反应如何?～s to the suggestions/sb's remarks/a joke/hearing what has happened 对那个建议/某人的话/一个玩笑/听到所发生的事情所作的反应;evoke/produce powerful (immediate)～s among the audience (in the young people) 在听众(年轻人)中引起/产生巨大的(即刻)的反响;Our～s get slower as we get older. 年龄越大，反应越慢。〖同〗response，reply;

(2)(药物等引起的)反应(any effect produced by a chemical substance or the action of a drug)[C;U，a～][N(to)]：Have you had a～to your injection? 你打针后有什么反应? a bad～to penicillin/certain tests/the drug 对青霉素/某些试验/那种药物的不良反应;an allergic～to pollen/birds/animals 对花粉/鸟类/动物过敏;produce no evil～不会产生不良反应;

(3)反作用力(force that balances opposite force)[C，U，a～]：action and～作用和反作用;rocket～火箭推力;the mutual～on each other of character and environment 性格与环境的相互作用;

(4)相反的感觉(倾向)(change of opinions or feeling，esp a return to an earlier condition)[U，a～]：This made him popular for a time，but then (a)～set in. 这使他一时间很受欢迎，但后来人们就不那么喜欢他了。There is a healthy～after swimming in winter. 冬天游泳后，会很健康的。

(5)反动(对)(opposition to political change，desire to return to a former system)[U][N(against)]：～against the new developments in the industry 对工业新发展的反对;Once again the forces of～prevailed/were de-feated. 反动势力再次嚣张/被击败了。

(6)化学(核)反应(process or condition of taking part in a chemical change;chemical changes)[C，U]：A chemical～occurs in the fuel cell. 燃烧室里发生化学反应。organic/nuclear/positive/negative～有机/核/阳性/阴性反应;

← re′act v;

→ re′actionary adj 反动的;n 反动分子