16.[2001全国] Visitors ________ not to touch the exhibits.

50.He ________ there, lost in thought. He felt as though he ________ for ever his power of judgement.

45.Ever since Picasso's painting went on exhibit, there ________ large crowds at the museum every day.

44.Look at the terrible situation I am in! If only I ________ your advice.

42.—I beg your pardon, but I didn't quite catch you.

—Oh! I ________ myself.

24.[1997全国] —Alice, why didn't you come yesterday?

—I ________ , but I had an unexpected visitor.

9.I should have written to you earlier, but ________ rather busy recently.

I didn't like Aunt Rose, who ________ without warning and bringing us presents.

Once the environmental damage ________ , it will take many years for the system to recover.

The number of the students in our school ________ 1,000.

A.　　  have added up to    B. adds up to 

C. has been added up to  D. is added up