The Nuclear Security Summit is an initiative of Mr. Obama, considers nuclear terrorism to be one of the greatest threats to international security.
In Jan., 2010, Xin Jiang was struck by so terrible a snow______few people had ever experienced before.
The failure to find a satisfactory job after graduation pushed him to____writing as a career.
---Poor John! I could hardly recognize him just now! ---_______. He has changed so much.
---You keep on coughing. What’s the matter? ---Oh, I’ve got a cold. Nothing serious, _______.
---I’m sorry that I didn’t work out this problem. ---It’s _____our ability. I didn’t work it out, too.