在英语中介宾结构是什么意思?介词后面的必须叫宾语吗?

介词宾语通常是用名词、代词、动名词、名词性从句等词类或结构表示的.但是,形容词、副词、介词短语、动词不定式等词类或结构在一定的情况下也可充当介词宾语.
A.不定式作介词宾语.可接不定式作宾语的介词有about,besides,but,except,save,instead of等.例如：
As I was about to say,you interrupted me.我正要说的时候,你插嘴了.
Autumn harvest was about to start.快要秋收了.
介词but,except,besides,save后的不定式,何时要带to,何时不带to,主要从三个方面去辨别.(1)当这些介词前面的句中出现了用作谓语的实义动词do时,其后的不定式就不带to；(2)当这些介词前面的非谓语部分有不定式to do时,其后的不定式符号to可用可不用；(3)当这些介词前面(即谓语动词或非谓语动词部分)无动词do时,其后要接带to的动词不定式.请再比较以下几例：
What could he do but take back what he had said?他除了收回他说的话外,还有别的什么办法?
“疑问词+不定式”构成的不定式短语,可用作任何介词的宾语.例如：
Everyone had his own idea of how to do it.任何人对如何做这件事都有不同的看法.
He gave a lesson on how to improve soil.他讲了一堂如何改良土壤的课.
B.形容词作介词宾语.可用形容词作宾语的介词有but,from,instead of,near等.例如：
My work is far from good (satisfactory/ complete.)我的工作离好(满意/完成)还差得很远.
It is anything but bad.这不是什么坏事.
Things went from bad to worse until Dickens' father was imprisoned for debt.情况越来越坏,直到狄更斯的父亲因负债而被关进监牢.
形容词作介词宾语还见于一些固定的习语中,这类习语常见的有at large,for the better,in short,in vain,like mad,on high等.例如：
We had to drive like mad to get there on time.我们只得尽快开车,以便能按时到达那里.
The policemen know who the culprit is,but they have not located him.He is still at large.警察知道罪犯是谁,但还没有查到他在何处,他仍逍遥法外.
C.副词作宾语.可用副词作宾语的介词有except,from,instead of,till等.例如：
Where are you from?你从何处来?
He has been studying hard except recently.他一直学习很刻苦,只是最近才不这样.
在from now (then),till now (then),for long,by far等习语中,都是副词做介词宾语.例如：
He will not remain for long.他不会呆得太久.
That will do for now.We will have a rest,and finish the job later.暂时干这些就够了.我们休息一下,等会儿再完成这项工作.
All property formerly belonging to the reactionaries is from now on the property of the people.以前属于反动派的一切财产,从今以后都是人民的了.
D.介词短语作介词宾语.可用介词短语作宾语的介词有across,except,from,instead of,since,to,till等.例如：
He usually goes to school on his bike except on rainy days.除了雨天,他通常都是骑自行车上学.
The cat appeared from under the table.猫从桌子下面出来了.
关于介词短语作宾语的用法,可参见6.1 B.
E.whether,that从句作宾语.由连接代词(如what,which,who等)或连接副词(如how,where,why等)引导的名词性从句作介词宾语是一种比较普遍的现象.在实际应用中,由纯连词whether或that引导的从句也可用作介词宾语,其中that引导的从句只能用在except,but,in,save等少数几个介词之后.例如：
He hesitated (as to) whether he would go to see her.他拿不定主意是否要去见她.
The molecules of ice and vapour are exactly the same,except that they move at different speeds.冰与水蒸汽的分子完全一样,只是它们运动的速度不同.
关于“介词+that从句”结构,有的语法家将其视为介词短语,其中的that从句用作介词的宾语；有的语法家则认为“介词+that”应看作复合从属连词.我们认为,这两种理解都有一定的道理,只不过前者主要是从语法形式上来看,而后者则是从语法意义上来看的.请分别从形式和意义上去理解以下几句：
Although the dividends are the same,this is the better investment in that it is a safe stock.虽然红利相同,但是这笔投资要好些,因为它的股票更为保险.