这期我们要来学习情态动词+完成时的用法,当然包括了大家最关心的虚拟语气. ! q$ z4 l( l; Y4 f
1. may和might+ 动词完成式, [' A% f) n6 d& }+ A. W$ F5 Y
此结构用于推测过去的行为。例如:
1 Z" y6 H" S6 C6 {) \3 | She said that he might have missed the plane.她说他可能误了航班。
. r8 w$ c6 C# }8 H. R. K 2. can和could+ 动词完成式
3 R' B9 ^4 F9 V) v A. 表示过去能做而没做的事,有一种对过去未付诸实施的事情的惋惜。例如:
$ }9 K! p0 P( C) g" T7 q# k In those circumstances we could have done better.% z. s- J F" I
在那样的情况下,我们本来可以做得更好的。(但没有做得更好)- t: a( e% H$ R# l
B. 推测过去的某种行动。
% c( A3 b8 f' i2 T# U Where can /could she have gone? 她可能到哪里去了呢?
: d0 h- F& E5 O' _' h" G0 \4 q& O The boy can't have finished reading the book so soon because it is difficult even to an adult.
2 h R0 w9 {$ g, [7 \) [; h 这孩子不可能那么快就把这本书读完的,因为即使对一个成人来说,这本书也是相当难的。
9 ?# j0 S1 p4 E Note:/ g5 N1 q3 F; X
can't和couldn't+ 动词原形可以用来表示否定推断。例如:3 q q6 j' ]* E# _
He can't be over fifty.他不可能超过50岁。
5 h' ?) c3 c, G' W 3.must +动词完成式! D) N4 }" a5 H' k2 @4 Y1 \5 ?, r
表示对过去行为的推断,具有较大的可能性,意为“一定…,想必…”。例如:
$ `4 z1 z. K7 f3 H She must have gone through a lot.. g: ^' W5 F" r2 ^# J2 B, F
她一定吃过很多苦。6 e5 a7 B6 c1 A, u2 I( W+ ~- ~
Note:( ~- N/ _. _' R
must+动词原形→对现在的推测,must be+现在分词→对未来或现在正在进行的推测。例如:# z ~# P: u t1 m" N
She looks happy; she must be having a good time.
. w; P5 {. _3 `& }& q 4. needn't+动词完成式和didn't need to do% ]+ O7 O* u: k- }: x. [
A. needn't+动词完成式表示一种已经做过的但并无必要的行为。例如:
, a0 O e1 a4 E; O+ |) C: O You needn't have watered the flowers, for it is going to rain.
4 S' K( K r6 Q0 i' F$ g1 V5 C; f 你本来不必浇花的,因为天要下雨了。(但却浇了)0 ~( h! N y+ s
We needn't have told him the news because he knew it already.
& C: G" x7 O, t' z+ J/ } B. didn't need (have) to do结构表示没有必要做某事,实际上也没有做。例如:0 J. }; r1 k2 |* h7 u* e3 m
I didn't need to clean the windows. My sister did it.% d/ Z, P% |( f4 }
我不必擦窗,我妹妹擦了。(我没有擦)7 l1 J v) F+ }# d* }
5. should +动词完成式+ D$ f1 b& `, w) |) m1 k
A.此结构的肯定式表示应该做的事而没有做,否定式表示某种行为不该发生但却发生了。例如:) J2 b0 i, J; s# j. ~
You should have given her more help.; R8 C; `& }/ y% f$ r' y+ s$ D$ x( e
你应该多给她一些帮助的。(但没有给)
7 J6 m6 M q; n! o3 ~3 j h B. 表示推测,意为“可能”,但可能性较小。例如:! m/ M9 v c) H: J' {. ` G
He should have finished the work by now.
}" Q6 o7 y% g, A8 q! L$ C 他现在该把工作完成了。(推测)
# d4 {! u4 I4 B6 B C. should / would have thought意为“本以为,本认为”。例如:5 p( x# g$ E* K0 }
A: "Can you type?"
+ @! _" Y1 M. N1 W8 C4 L B: "Certainly."
# C4 w0 T! P# R- U' k* e) Z A: "Well, I should have thought you wouldn't."
( T, h1 F1 [5 Z3 j I should have thought she wouldn't agree.
I; w9 @4 h0 t% n) Z4 o" } 我本来认为她不会同意的。
+ N+ r: K5 ]0 ^% _1 ] D. should have thought有时意为“认为,以为”,相当于should think,但表示更为委婉、谦逊或不肯定的语气。例如:
, U, Y# `: V! o7 y6 L: i' D I should have thought it fairly good.
4 h; Z$ ]- H% N! ~: L9 K1 n! w 我以为它是很不错的。
6 y C- @' l, H. {8 u8 @ x E. should have + 过去分词用于虚拟语气:6 p" I# R% O) K9 }- G
Had you written him, you should have known the details.
' s ]* `/ t, v% _ 6. ought to + 动词完成式
; i8 L0 c" u6 J1 Y8 h/ r6 C 此结构表示某种过去应该做而没有做的事,或被忽略未做的某种明智行为。例如:+ Z: @. [, c, [( h9 v7 i
You ought to have returned the book earlier.(还晚了)
/ _6 H7 P& }$ G) P& t) c You ought to have refused her at the beginning, but now it is too late.
8 C1 P B4 C/ I9 U7 ^( z4 N Note:& `$ w. L) Z1 `! S! Z1 [9 J
这里的ought to也可以用should代替。
' }6 D7 ^: f3 P. ^ Homework:用给出的动词填空,注意要选用正确的助动词和时态.3 u- Z6 { T0 u3 _4 c- w
1.The boy____ the book so soon because it is difficult even to an adult. (read) 6 V" _$ D, x4 j0 N& l
2.We___him the news because he knew it already. (tell)
: |( y/ r# t9 l0 A& J4 f 3.If we had taken the other road, we ____earlier. (arrive)
5 K* W& O, ?( v$ q2 a 4.I _____you might take this into consideration. (think) 6 Q2 v6 q2 [ _& m) Y) ~% A' K
5.You ____ her at the beginning, but now it is too late.(refuse) |