25. We consider __________the instrument be adjusted each time it is used.  
A. that it necessary          B. it necessary that  
C. necessary that            D. necessary of it that
答案：B形式宾语it的用法consider +it +adj. + that…it做形式宾语，真正的宾语是that后的从句。

26. __________, we decided to leave at once, as we didn't want to risk missing the bus.  
A. As it being pretty late     B, It being pretty late  
C. It was being pretty late    D. Being pretty late
答案：D非谓语动词的用法，本句为现在分词短语做原因状语，分词的主语和句子的主语一致。

27. __________ was once regarded as impossible has now become a reality.  
A. What                 B. That  
C. Which                 D. As
答案：A主语从句的用法，What was once regarded as impossible为主语从句。

28. Mr. Smith, together with his wife and children, __________ going to the party this weekend.  
A. am                     B. is  
C. are                      D. will
答案：B主谓一致，本句的主语是Mr. Smith, together with his wife and children 是插入语。不改变主语的数。

29. Would you mind __________ the computer game in your room?  
A. him playing             B. his playing  
C. him to play              D. him play
答案：B动名词的用法，min doing sth介意做某事做宾语。当动名词前有某人做其逻辑主语时。用其形容词性的物主代词。

30. By next year he __________ in New York for five years.  
A. has worked              B. has been working
C. works                  D. will have worked
答案：D将来完成时，以By引导的将来的时间后面接将来完成时。

31. Henry is often seen __________ English aloud every morning in the classroom.  
A. read                   B. reads  
C. reading                D. to read