they are twins, they don’t look the same at all.

--- Mr. Green, I think physics is too difficult for me. ---Tom, work hard, _______ you’ll find it not as difficult.

—Avatar is ______ that I have seen it for three times．—Though it is very popular all over the world，_____it didn’t win the best film of Oscar this year．  

 Milk quickly goes bad in summer       it is in a fridge (冰箱). 

____ Mr. Zhang gave us some good suggestions, but we still didn’t deal with those problems very well.