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.
2 B" K" [! g; S9 m 1. may和might+ 动词完成式0 Z: n# `$ y' s6 ^3 D9 }: \0 g" c2 e1 U
此结构用于推测过去的行为。例如:
; @% N/ g3 g! Y# V2 U. U, S She said that he might have missed the plane.她说他可能误了航班。
# a3 `% G& s9 i. ] 2. can和could+ 动词完成式
% d' S( {, L7 D1 ?: ^ 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:" |# j K* G. G) D) e( F: g) ~
In those circumstances we could have done better.
6 ]) B# Z5 H# O+ H7 _0 X 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)
$ D- O2 }6 M* z% B% n1 X B. 推测过去的某种行动。
( L6 w3 h/ ]5 L Where can /could she have gone? 她可能到哪里去了呢?
9 D( V( J4 g) ? The boy can't have finished reading the book so soon because it is difficult even to an adult.
1 S: X6 n: [0 f5 p 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。0 V7 ~/ @6 Q3 U/ n
Note:2 G8 y4 ?* B# J* ]+ k4 B
can't和couldn't+ 动词原形可以用来表示否定推断。例如:" P0 g% A2 j. f* R, u% D4 ~
He can't be over fifty.他不可能超过50岁。' L( R* t- D9 j
3.must +动词完成式& n" U- y: z9 O1 @6 P, n
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:" g; H) |$ }3 P# Y& I
She must have gone through a lot.& [0 ]# l3 f8 n9 q
她一定吃过很多苦。! J3 T6 s) n; I, z+ j% Z
Note:0 Z; p' O4 K4 \% I 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: F& q. l, Z) b. Z% @' ]- S
She looks happy; she must be having a good time.
1 B0 L" K8 c# c4 v% J3 \+ C 4. needn't+动词完成式和didn't need to do
7 w/ ~7 d3 W. [* H* m4 @- z 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:" e. b3 u" {$ d% h+ o* z0 @
You needn't have watered the flowers, for it is going to rain.
" B( N7 p, `6 d8 k/ E7 @ 你本来不必浇花的,因为天要下雨了。(但却浇了)
' ]' z* B5 k# W( y; } We needn't have told him the news because he knew it already.
% M" g; s3 q- n 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:% U7 V; V5 M# f' n7 p
I didn't need to clean the windows. My sister did it.
& N& J7 m' S! R! y 我不必擦窗,我妹妹擦了。(我没有擦)
2 n- g( H5 Z% y2 }% A; d 5. should +动词完成式& s" a5 \6 V# N$ U- I) M. i4 h: ?4 g
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:+ _0 ?- I7 |/ X9 u2 v/ Q5 ?! Y
You should have given her more help.* e0 d9 d+ z( u6 l) b+ ^
你应该多给她一些帮助的。(但没有给); T; K& d8 l$ g* v* j
B. 表示推测,意为“可能”,但可能性较小。例如:
+ w5 @1 h1 t$ I/ [" {- J0 k0 Y6 {8 f He should have finished the work by now.2 f# X' |! [# A' n! Z
他现在该把工作完成了。(推测)
! _$ m8 w5 ~' v, L a3 H5 q C. should / would have thought意为“本以为,本认为”。例如:
" b3 g" G- r- o7 |7 x& w A: "Can you type?"
& d9 h' g: d7 H# b B: "Certainly.": d& n3 S7 F! E" ^! \2 P) f
A: "Well, I should have thought you wouldn't."
& C! A. n$ H5 Y0 d" ] I should have thought she wouldn't agree.
2 O& N, a9 }. c7 V% ~" y5 x 我本来认为她不会同意的。! z& }9 I# ^9 l; p5 |
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:
' @! v4 P8 _9 s! V+ c6 c% U I should have thought it fairly good.
( Q8 Y7 r; ?2 q. v& i/ i2 Q K! z 我以为它是很不错的。
7 M: _- I( i7 O" d* @. j( F/ W5 Y' S+ R E. should have + 过去分词用于虚拟语气:
- H% ]+ o& @' J) [6 V Had you written him, you should have known the details.
4 W1 ]4 O. k$ M4 g H& W 6. ought to + 动词完成式
' e0 D/ V- ^; R& \! H 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:
6 H- b; ?0 U. L" C, ?% ~ You ought to have returned the book earlier.(还晚了)
: I( `* }6 c- }% w- z3 |' k You ought to have refused her at the beginning, but now it is too late.
" W& ], \( I# [ s Note:
: P9 _% ~) e" T 这里的ought to也可以用should代替。 h* \4 x( F- k, S5 n* n3 K7 s2 [
Homework:用给出的动词填空,注意要选用正确的助动词和时态.
# m+ W0 j1 @5 Q! ^9 A: a 1.The boy____ the book so soon because it is difficult even to an adult. (read)
: t* {3 T, D1 {* N1 x# ?, ? 2.We___him the news because he knew it already. (tell)
' q% `4 v. u7 i/ a' B 3.If we had taken the other road, we ____earlier. (arrive)3 J9 D8 d% e6 {) m
4.I _____you might take this into consideration. (think) 4 a4 A- d, @/ }+ _3 j
5.You ____ her at the beginning, but now it is too late.(refuse) |