25. The __________ of the sofa is high, we don’t have enough money to buy it.
     A. size                B. weight              C. price
26. Jerry won first prize in the speech competition. His parents are proud of his_______. 
    A. accident              B. success             C. wise
27. The twins look so _______ that I can’t tell one from the other.
    A. similar               B. fantastic                  C. expensive
28. — I find it difficult to learn Physics well.
    — That’s true. Nobody can learn it well _______ he works hard at it. 
        A. if                  B. because            C. unless