It’s hard to tell real Jingdezhen vases, and it’s a little more difficult for the untrained shopper to______.

  Father said he would come to my graduation ceremony, he didn't, _______.

 Achieving a high degree of proficiency(精通）in English as a foreign language is   not a mysterious _______ without scientific basis.

 I’m glad you told me about the concert being cancelled. ____ I’d have traveled all the way to Beijing for nothing.

I called Mom yesterday and she said she had something delicious ____ for me.