Some scientists recommend that nano particles be treated as new chemicals with separate safety tests and clear labelling.选自剑桥雅思10T4 S4.
请问这里为什么是be treated 而不是is treated 或是 are treated?
be treated 前面省略了 should。这与动词 recommend 有关,即 recommend 后面接宾语从句时,宾语从句的谓语动词通常用 should + 动词原形(其中的 should 也可以省略,如果省略了 should,就只剩下原形;如果是被动语态,省略 should 就只剩下 be + 过去分词)。又如:
I recommend that he (should) buy this book. 我建议他买这本书。
The committee recommended that the chief executive (should) be dismissed. 委员会建议罢免总经理。
I’m not the person to recommend how the job (should) be done. 我不是能为做此事出主意的人。
Doctors recommended that the drug (should) be taken off the market. 医生建议市面上应停止出售该类药物。
下列动词用于所给词义时,其后用that连接的宾语从句中用虚拟语气:如果从句谓语动词是被动语态,就用 (should )be + 过去分词(英式英语通常保留 should,美式英语一般不用should ):
advise(劝告), advocate(提倡), agree(同意), appoint(下令), arrange(安排), argue(主张), ask(要求), command(命令), decide(决定), decree(命令), demand(要求), desire(请求), determine(决定), direct(命令), dictate(命令), expect(希望), insist(坚持), intend(打算), legislate(立法), maintain(主张), move(提议), order(命令), object(反对), permit(允许), persist(坚持), petition(请愿), propose(提议), prefer(宁愿), pray(恳求), provide(规定), request(要求), recommend(建议), require(要求), resolve(决心), sentence(判决), specify(指定), suggest(建议), stipulate(规定), urge(主张)
......
The committee recommends that the budget (should) be discussed at the next meeting.委员会建议下次会议再讨论该预算。
(摘自《刘毅英语语法宝典》pp.372-373)