What’s the reason for twins to be at a disadvantage in their intellectual development?

• A、They can only understand their own private language．

• B、They communicate with outsiders less than non-twins．

• C、There is little stimulation for them．
  

• D、Adults don’t like to talk with them．

 你是Lucy，寫一封給老同學Allen的邀請信，邀請他參加下個星期日下午4點(12月23日)的校友聚會。希望Allen盡快回信接受邀請，以便他們及時做好安排。

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• A、giving 
  

• B、given   
           
  

• C、offering 

• D、taken