Unit 13 The water planet教學設計

  your mother must have been looking for you. 你媽媽一定一直在找你。
5）推測的否定形式，疑問形式用can't, couldn't表示。例如：
mike can't have found his car, for he came to work by bus this morning.
邁克一定還沒有找回他的車，因為早上他是坐公共汽車來上班的。
  注意：could, might表示推測時不表示時態，其推測的程度不如can, may。
7 情態動詞+ have +過去分詞
1） may（might） have + done sth, can （could） have + done sth 表示過去，推測過去時間里可能發生的事情。例如：
 philip may （might） have been hurt seriously in the car accident. 菲力浦可能在車禍中受了重傷。
 philip can （could） have been hurt seriously in the car accident.
2） must have +done sth，對過去時間里可能發生的事情的推測，語氣較強，具有"肯定"，
"諒必"的意思。例如：
   ---linda has gone to work, but her bicycle is still here. 琳達已經去上班了，但她的單車還在這兒。
   ---she must have gone by bus.肯定乘巴士去的。
3） ought to have done sth, should have done sth表示本應該做某事，而事實上并沒有做。否定句表示"不該做某事而做了"。例如：
 you ought to （should） have been more careful in this experiment. 你當時在做試驗時應該更仔細點。
 he ought not to have thrown the old clothes away.他不該把舊衣服扔了。（事實上已扔了。）
 ought to 在語氣上比should 要強。
4） needn't have done sth表示本沒必要做某事，但做了。例如：
i dressed very warmly for the trip, but i needn't have done so. the weather was hot.
 旅行時，我衣服穿得較多，其實沒有必要。那時天很熱。
5） would like to have done sth表示本打算做某事，但沒做。例如：　
 i would like to have read the article, but i was very busy then. 我想讀這篇文章，但太忙了一直沒讀。
8. should 和ought to
除了上述的用法，兩者還可表示"想必一定，按理應該"的意思。例如：
i ought to be able to live on my salary. 靠我的薪水，想必也能維持了。
it ought to be ready now. 想必現在準備好了吧。
they should be there by now, i think. 現在他們該到那兒了。
the poems should be out in a month at most. 詩集估計最多還有一個月就要出版了。
9 had better表示"最好"，相當于一個助動詞，它只有一種形式，它后面要跟動詞原形。例如：
 it is pretty cold. you'd better put on my coat. 天相當冷。你最好穿上我的外套。
 she'd better not play with the dog. 她最好不要玩耍那條狗。
 had better have done sth表示與事實相反的結果，意為"本來最好"。例如：
 you had better have come earlier. 你本該來得早一點。
10 would rather表示"寧愿"
  would rather do
  would rather not do
  would rather… than… 寧愿…而不愿。
  還有would sooner, had rather, had sooner都表示"寧愿"、"寧可"的意思。例如：