Ⅰ.重点单词
1．volunteer n. 志愿者 v．自愿
volunteer to do sth.主动做某事
voluntary adj.自愿的；志愿的
2．prefer vt. 更喜欢；选择某事物(而不选择其他事物)
preference n．偏爱；喜好；优先权
preferable adj.更可取的，更好的
in preference to优先于；而不是
have a preference for sth.偏爱某物
give preference to...优先考虑……，优待……
prefer doing sth.＝prefer to do sth.喜欢做某事
prefer sb. to do sth.＝prefer that sb.(should) do sth.宁愿某人做某事
prefer (doing) sth. to (doing) sth.与……相比，更喜欢(前者)
prefer to do...rather than (to) do...宁愿做……而不愿做……
