很多同学都能想到用was to来填空,但是后面的时态却都用了attend.有人问为什么要用完成式.因为5 K8 m% D0 ^' L1 y. j
was (were) + 不定式完成式,这种结构表示“本来打算…,本来要…(而结果则没做)”。8 {& M+ `( E4 I+ I, @
这个知识点很重要啊,大家可要牢记在心呢.好啦,今天我们要来复习的是have to和must:
8 K: I5 A' o( K# R' Y+ ` have to 和must在表示“必须”这个意思时是很接近的,但也有一定的区别。
* G8 C( ?6 B: @( t1 \ 1. have to 比较强调客观需要,表示因客观环境或事态促使而不得不做某事;must强调主观看法,表示主观上认为有必要做某事。例如:4 a5 {1 t8 d# E A
I must learn another language.
8 H7 B" g9 L n1 @& S; S (主观想法: I want to)
- e6 g8 _! Y3 O* c; A I have to learn another language.4 Y, q6 R0 w s
(客观需要:身为一个外交官)
; [: w9 U4 Q7 W7 c O7 [) { You must be back before 10 o’clock. ' R8 M1 J6 N" k. c$ O
(叮嘱或命令)8 Q. P2 u0 Q/ J+ g1 ~+ C* A
You have to be back before 10 o’clock because the train is to leave at 10:05.(客观需要)
& C* O) _; Q0 F$ ~( m& w 2. have to多表示义务或习惯动作;must则用于表示一种重要或急迫的事情。例如: & n# q! a9 q+ u
We have to care for the young.(义务) D i- j* ~" }) j: `2 d
She has to be at the office before eight every day. (习惯)
! c9 C' T7 q: x' r' e You must go to the manager at once, or you’ll be dismissed.+ o# }; h' P+ ~' e
务必马上去见经理,不然你会被开除的。(急迫的事情); y; J# [1 P8 b' D
3. have to可用于不同的时态;而must一般只用于现在时(但也可以表示将来的情况,在间接引语中也可以表示过去时)。例如:% E5 |$ q0 S% [5 e' m% ^
I have to (must) leave now.
7 u3 r' Z- u6 J; o# | We’ll have to buy another TV set.0 J) i& G* r! i- }
They had to put off the sports meet because of the bad weather.
6 p4 s9 b: ~1 A* r! o l- `1 M0 S He said that the work must be finished within two weeks.; f. ^! |# P! ^' K" t, ]( q
4. must还可以表示一种推断和揣测,而have to则不能。例如:/ f% N7 w- m& @3 F' ~3 j2 L
This must be Jin’s pen.) N" L0 }9 S1 G
5. "must+动词完成式"可以用来表示对过去情况的揣测,而have to则不能。例如:
1 P" c# a) V( a& @0 Q- V7 ?" {. C She must have read the book sometime in the past, or she couldn’t have answered the question so well.
. K) ]8 J" u, `& \( s+ V5 n, Q 她一定在过去某个时候读过这本书,不然,这个问题她不会回答得这么好的。
+ c* a6 E- ]& F6 f; k3 q Note:
! T2 G% ^" n0 T H 在现代英语中,have to 中不定式和疑问句式既可以按照助动词的变化规则构成,也可以按照行为动词的变化规则构成。例如:
, j$ Z( ]: K- p; j* r# @' z Have you to finish the work before supper?
$ V; X9 I7 m1 ^: b+ i* ?9 k& m Do you have to finish the work before supper?& p4 X8 V% }+ ~9 ]+ {- K8 d
have got to 常可同have to换用,但有时表示不同的含义。比较:# D2 C% Y5 j! y" k7 s* h
He has to report to the headquarters every two days.(例行公事,习惯动作)9 j0 D" r' G( r/ |6 X% C" H# x
He has got to report to the headquarters every two days.(一道指示或命令,必得每天报告一次). ~+ O' o! S/ z
另外,作“有”解时,have got和have通常是可以换用的,have got更口语化,但有时表示不同的含义。比较:% a2 _: l4 N. {+ z: Q3 o4 j
The man has a blind eye.那人有一只眼瞎了。# X, G5 I8 G8 ?, X/ u8 n) E
The man has got a blue eye.那人有一只眼被打青了。7 K: V- `- g2 k' J% d
must not表示禁止,是说话人强有力的劝告或命令,意为“一定要,不准”。因此,在回答由must引导的问题时,如果是否定的回答,表示“不必,没有必要”,不能用mustn’t,而要用needn’t或don’t have to.试比较:. ?/ m. J6 x0 @! l2 ~) O b( V
You must not drive fast.你不能开快车。(路险或有速度限制)
* s n6 M4 z: H1 U You needn’t drive fast.(时间充裕) |