基本介紹
- 中文名：半助動詞
- 外文名：Semi-Auxiliaries,Semi-modals
- 定義：主動詞和助動詞之間的一類結構
實例,其他用法,轉換關係,省略式,注意,
實例
The boy has to make a living by begging.
男孩不得不通過乞討維持生計。
He is unwilling to help me with my English.
他不願幫我學習英語。
Every clause is obliged to obtain a finite verb.
每個句子必須包括一個限定動詞。
We were about to start when it rained.
下雨時，我們即將出發。
He seems to be very disappointed.
他好像非常失望。
I don’t have to buy a new house.
我不必買新房子。
He didn’t seem to feel in love with her.
他好像沒有愛上她。
其他用法
帶有半助動詞作為動詞詞組的組成部分的句子，有的可以轉換為“ It…that-分句”結構，而有的卻不可以。從這個角度看，半助動詞可分為兩類：一類是可以作上述轉換的，其中包括be cer-tain to，be（un）likely to，appear to，happen to，seem to等。例如：
They are certain to win the game．他們肯定會在比賽中獲勝。
→It is certain that they will win the game．
He is likely to let you down．他可能使你失望。
→It is likely that he will let you down．
He appears to have many friends．看來他有許多朋友。
→It appears that he has many friends．
He seems to be enjoying himself．看來他玩得很快活。
→It seems that he is enjoying himself．
I happen to have had some nasty experiences in dealing with him．
我恰巧有過一些和他打交道的不愉快的經歷。
→It happens that I have had some nasty experiences in deal－ing with him．
Some members of the committee seem to have been bribed．
委員會的一些成員看來是受了賄賂。
→It seems that some members of the committee have been bribed．
另一類半助動詞不可以作上述轉換，這一類包括be about to，be bound to，be going to，be to，had better，have to，have got to，tend to 等。例如：
He is adout to arrive．他即將到達。
He is bound to win!他一定會獲勝！
The boy tended to be late．這孩子老是遲到。
不可以轉換為：
*It is about that he will arrive．
*It bound that he will win．
*It tended that the boy was late．
半助動詞也可用於there－存在句。例如：
There's going to be a storm．就要有暴風雨了。
There's to be an investigation．要作一次調查。
There has to be a mistake．一定有錯。
There's sure to be some rain tonight．今晚一定有雨。
There's likely to be a large audience．觀眾人數可能很多。
There's certain to be trouble at the factory．廠里一定有麻煩。
There seems to be a widespread change of attitude
看來態度有普遍的改變。
There appears to be no doubt about it．
看來這是毫無疑問的了。
轉換關係
凡是能夠作上述句型轉換的半助動詞，在there-存在句中，也可作類似的轉換。
現在，我們再從相反的方向來看這種轉換關係：
It is likely that there'll be a large audience．
→There is likely to be a large audience．
It is certain that there is trouble at the factory．
→There is certain to be trouble at the factory．
It seems that there's a widespread change of attitude．
→There seeme to be a widespread change of attitude．
It appears that there's no doubt about it．
→There appers to be no doubt about it．
順便說一句，如果“It…that+there-存在句”的主句謂語動詞是is said，is believed等被動態，那末轉換過來的there-存在句的謂語動詞也應是被動態。例如：
It is said that there's trouble at the factory．據說廠里有麻煩。
→There's said to be trouble at the factory．
不過，這裡的is said to（be）已經不是半助動詞了。
省略式
在結束本節以前，還要提一下半助動詞的省略式問題。在口語中，had better，have got to和be going to有時可用省略式。例如：
You（'d） better go now．你最好現在就去。
You（'ve）just got to help．me．你得幫幫我呀。
Where（are） you going to get the money from？
你準備從哪兒去弄這筆錢？
UNESCO CHIEF TO VISIT AFRICA
聯合國教科文組織領導人將出訪非洲
注意
下面一些結構中的to-不定式是作主語補語用，而不是半助動詞be to+不定式。例如下面兩句均作“最好的還在後頭”（The best is still ahead of us，in the future）解釋，其中的to come和to be均作主語補語用：
The best is still to come．
The best is yet to be．
還有一些結構在語法上可作不同理解，既可看作形容詞詞組作後置修飾語，也可看作關係分句的省略形式。例如：
Those likely to arrive after 7 p．m．should notify Mrs Thomas before 14 March…
可能在下午7點以後到達的人需於三月十四日前通知托馬斯夫人……
In desperation it（指her mind）lit upon the figure of her father already broken in health and now about to die．
在絕望中，她腦海里突然出現了她那早已病魔纏身，如今已奄奄一息的父親的身影。
Becarse I was the player least likely to be used in that game，I was the one sent to forage．
由於我是一個最不可能被選拔參加那場比賽的隊員，因此就派我出去搜尋糧秣。
在上述諸例中，likely to arrive after 7 p．m．，now about to die，least likely to be used等都既可看成形容詞詞組，也可看作關係分句的省略形式。如果作後一種分析，就涉及半助動詞的問題．例如Thoselikey to arrive after 7 p．m．相當於Those who are likely to arrive．．，在這裡，are likely to是半助動詞（本書是這樣處理的）；當然，who are likely to arrive…也可以看作是“主—動—補”結構。這也就是說，像“are likely to+不定式”這一結構既可作為一個整體來看待（即看作半助動詞+不定式），也可分開來看待（即將該形容詞看作主語補語）。由於likely，sure，certain等都是形容詞，從而也可以接受副詞的修飾（如上述後兩例），並有比較等級形式。例如：
It might be very well if dramatists were philosophers，but in point of fact they are as little likely to be so as are kings．
要是劇作家同時又是思想家的話，那該有多好，可是，事實上劇作家不可能同時又是思想家，正如國王毫不可能同時又是思想家一樣。
在這裡，as little likely to be so as are kings似以看作形容詞詞組作主語補語為宜，否則便把事情搞得過於複雜化了。
