中文字幕精品视频在线|中文字幕在线观看|亚洲v日本v欧美v在线播放|伊人网中文字幕

<nav id="3u6n6"></nav><samp id="3u6n6"><tr id="3u6n6"><track id="3u6n6"></track></tr></samp>
    <legend id="3u6n6"><fieldset id="3u6n6"></fieldset></legend>
      

      

      2. 
		
		
      
			
			
      
				
			
      
			
			
		
      
    
      
        
      
            
      
                
                    
      
	
      PR
      
	
      ['pi 'ɑr]

      


	    
      
	
        
    
      • abbr. 公共關(guān)系（public relations）；性能要求（Performance Requirement）
        • 
    
      
	
      

      

    
      英英釋意
      
	
      
	
      1. a soft yellowish-white trivalent metallic element of the rare earth group; can be recovered from bastnasite or monazite by an ion-exchange process