11) The subject of these lectures ____by the lecture committee.
A) is announced
B) have been announced
C) are announced
D) has been announced
12) I found an aspirin bottle ____dropped on the floor of David's room.
A) was B) had C) had been D) is
13)The goods ____when we arrived at the airport.
A) were just unloading
B) were just been unloading
C) had just unloaded
D) were just being unloaded
14) If one ____by pride,he will reject useful advice and friendly assistance.
A) overcomes B) is overcomeC) has been overcome D) overcome
15) Most environment problems exist because adequate measures for preventing them ____taken in the past.
A) was not B) were not C) were not being D) had not been
16) You ought to have put the milk in the refrigerator,now ____sour.
A) I smell B) it is smeltC) it smells D) it is smelling
17) After the race____,the celebration began.
A) had been won B) is wonC) will be won D)has been won
18) He was here for a little while,but I don't knowswhereshe ____now.
A) is B) was C) had been D) has been
18) The young teacher has ____ competent.
A) been proved to be B) proved to beC) been proved D) proved being
19) Pluto,the outermost planet of the solar system,____photographically in March 1930.
A) discovered B) was discoveredC) by discovery D) when discovered
20) To get a better view of the stage,____.
A)our seats had to be changed
B) our seats were changed
C) we had to change our seats
D) our seats were changed by us