9 这是advise的通常用法

问：在阅读The Vitamin Debate一文时遇到这样一个句子：（1）For years，doctors advised their patients that the only thing taking multivitamins does is give them expensive urine.该句的结构我不太清楚，请问is后面是否缺少to？该句的语法结构应该如何分析？

答：常用词advise用作及物动词，其意为：“向……提供意见；告知，通知”（to give someone an opinion about what to do，to give someone a piece of information about something），常见用法是advise somebody that clause，后接复合宾语。例如：

（2）They advised him that this was their final notice.

（3）We are to advise you that the matter is under consideration.

你所提问的句（1）中的advise即是这种用法：主句（main clause）是doctors advised their patients，从句（subordinate clause）是that the only thing…is give them expensive urine作直接宾语；宾语从句中又含有一个定语…taking multivitamins does修饰其先行词the only thing，可见，句（1）是一个复合句（complex sentence）。应该注意，advise后接复合宾语中的从句也可以是wh-clause，advise还可后接由不定式构成的复合宾语（complex object）等。例如：

（4）Would you advise me where I should spend my holidays this summer？

（5）Please advise me whether I should accept the offer.

（6）The doctor advised the patient to have a soft diet.

句（1）中的谓语部分is to give中省略了to，这并不罕见，be to do（to do是表语）之前若有实义动词do（does），常省略其后的to。例如：

（7）“All I did was（to）hit him on the head,”said the boy.

be to do是一个固定用法，有很多意思，可表示“注定发生，已经发生”（expressing destiny, possibility；showing what had to happen or did happen），表示一种可能性。例如：

（8）This discovery was to have an effect on the treatment of heart disease.

（9）I met her first in 1950. I was not to meet her again for forty years.

也可用被动式be to be done，例如：

（10）Highrise apartments are to be seen everywhere in Beijing.

（11）Similar conditions are to be found in all other Latin American countries.

此外，be to do还可表示“将要，打算”（shows arrangement for the future, intention or purpose），与be going to do相近。例如：

（12）The book of Fairy Tales I edited is to appear soon.

还可表示“命令、规则”（expressing an order or rule），与should do，must do，ought to do，have to do等近义。例如：

（13）I am to see her tomorrow at the latest.

（14）You are not to smoke here.

（13）和（14）两句的不定式符号均不可省略。