could 

  1. 助動詞
can過去式: could ...(動詞...):
(假設性地)可以做.../
能做...
(能力、功能上)會做...
could have ...(過去分詞動詞...):
本來可以做...
本來有辦法做...
本來有可能做...
could be ...(動詞ing ...):
可能在做...

    
                        
    2. 
                                                                        
  2. 

    語法
(問句)Could ...(人事物):
(婉轉或假設性地問)...可以嗎?/
...能嗎?
(問句)Could ...(A: 人事物) ...(B: 動詞...):
(婉轉或假設性地問)(A)可以做(B)嗎?/
(A)能做(B)嗎?
(問句)Could ...(A: 人事物) be ...(B: 動詞ing ...):
(A)可能在做(B)嗎?
(A)可以在做(B)嗎?
(問句)Could ...(A: 人事物) be ...(B: 人事物)/

    


    
                        
    3. 
                                            

                

            

            
            

                

                
例句

                

                    
    
                                                    
  1. 
                                All Santa could do was say no.                            
    2. 
                                                    
  2. 
                                He could have said Peter saved him.                            
    3. 
                                                    
  3. 
                                He trembled so he could hardly talk.                            
    4. 
                                                    
  4. 
                                I could sleep anywhere and any time.                            
    5. 
                                                    
  5. 
                                If only she could cease to remember.                            
    6.