required 

  1. 形容詞
必須的
必修的

    同義字詞
compulsory,forced,imperative,incumbent,involuntary,mandatory,necessary,nonelective,obligatory,peremptory
all-important,critical,essential,imperative,indispensable,integral,must-have,necessary,necessitous,needed,needful,requisite,vital

  2. 動詞
require過去式與過去分詞:
及物動詞:
需要...(事物)
要有...(事物)
要求...(事物)
(人事物)be required to ...(動詞...):
被要求做...
(人)被命令做...
required ...(a: 人事物) to ...(b: 動詞...):
需要(a)做(b)

    
                        
    3. 
                                            

                

            

            
            

                

                
例句

                

                    
    
                                                    
  1. 
                                No payment is required for enrollment.                            
    2. 
                                                    
  2. 
                                The injury required six months of rest.                            
    3. 
                                                    
  3. 
                                Safety goggles may be required during use.                            
    4. 
                                                    
  4. 
                                It's free, with advance reservations required .                            
    5. 
                                                    
  5. 
                                For approximate concrete required see chart below.                            
    6.