2. 语义加工
语义加工主要关注语义的迁移、语义变化、词义及词与词之间的关系。教师通过微型语境即上下文猜词义、英译汉、汉译英、填空、归纳等让学生理解目标词的词形变化、一词多义及具体用法。以重点词alarm为例：
alarm第一次出现在教师提供的有关野生动物困境的语篇中，是以形容词alarming的形式出现的。学生可根据上下文推测alarming的意思是“令人惊恐的”。教师提供微型语境，让学生猜测alarm的多种词义，并通过填词和汉译英帮助他们掌握alarm的两个形容词的词义和用法。学生归纳alarm的两种词性及相应的语义和用法（见图4）。
至此，学生已经理解了目标词的意义和用法。这是学生调动原有知识、经验和能力对信息进行主动构建。此时，教师要创设一些产出性活动，高质量复现目标词，提升学生的词汇运用能力。根据单元子话题，教师设置了相应的产出性活动（见表2）。
在活动1中，有学生提到大熊猫。
S1：The panda is one of the endangered species. Around the world，less than 3000 are alive. They’re in great danger of extinction.
T：Yes. Hopefully，they won’t be e_______.（建议答案：extinct）
当该生谈到单元目标词extinction时，教师及时引导学生说出它的形容词：extinct。可见，学生已掌握了extinction及其词根extinct的意义和用法。
在活动2中，有学生（S2）回答：“As far as I know，the reason why pandas are in danger of extinction is their habitat loss，which is caused by human activities. They always want to build more buildings and they have been polluting pandas’ living environment. As a result，the number of pandas is decreasing at an alarming rate.”
T：Good point. Everyone，could you think out why people always want to build more buildings?
Ss：They want to make more money. The population has been becoming larger，so they need more space to live.
T：Yes，so we have to say that humans destroy pandas’ habitats just for ___________.（建议答案：themselves）In other words，wildlife’s plight is due to human activities caused by their greed，selfishness and ignorance.
由此可见，在不同的语境中复现目标词alarming、extinction、habitat loss，能够让学生及时掌握其语义和用法。
在活动3中，学生小组合作思考、讨论改变野生动物困境的措施。某个小组讨论成果分享如下：
We try to think out some measures to protect pandas. First，shoot more videos to record their loveliness. Struck by it，more people are more than willing to protect them. Second，their habitats should be protected well. Also，more reserves are expected to be built and expert scientists help them have more baby pandas. Last，turn to the WWF for help. Make more people aware that many animal species cannot adapt to the changes brought about by the modern society.
不难看出，通过这3个活动，学生基本掌握了所学目标词。
（三）合作式搭建词汇语义网
在以上一系列活动中，学生根据词性、词语的习惯搭配和主题内容，悄然搭建单元词汇语义网，但还没成形。接下来，教师可以根据主题，引导学生合作探究，使用思维导图梳理词汇，将单元词汇语义网显性化。一对同桌合作的单元词汇语义网见图5：
