A. since (They have been in love for a long period of time that started in the past)
D. was cleaned (The action of cleaning was completed before you arrived)
A. have had (Since implies a continuous action up to the present)
C. had watched (The film was watched in the past)
B. my mother came back (The action of your mother coming back happened in a specific point in the past)
C. stands (The boy is standing now at the desk)
B. will have saved (By September, the saving will be completed)
A. was doing (He fell asleep while he was in the process of doing homework)
A. had washed (Washing the clothes happened before she started watching TV)
B. consists (Water is composed of hydrogen and oxygen now)
D. am studying (You are currently studying)
A. has not written (She hasn't written since last year and the state continues)
C. had watched / was watched (The police watched the thief who was already there)
Omitted question (Question 29 is missing)
A. will have conquered (By 2050, medical technology will have achieved conquering diseases)
D. had turned off (Before you left the room, you had already turned off the lights)
B. were talking (The action of talking was ongoing when the teacher came in)
A. have studied (Before the exam, you should have already studied)
C. phoned/ was writing (Jack phoned while you were writing a letter)
A. is sleeping (The baby is currently sleeping)
A. is washing / often washes (Mary is washing clothes now, and she often washes them on Sundays)
D. will have finished (After finishing her degree, she will work in her father's company)
B. will be / will have forgotten (By the time you come back, I think you will have forgotten me)
D. plays (Since you moved in, your neighbor has a habit of playing the stereo loudly every night)
C. was driving (This time last week, you were in the process of driving to Dalat)
A. have ever visited (This is the first time you have ever been to London)
B. has been made (Progress has been happening continuously since 1950)
B. have been (This is not your first time being here)
D. had read (She read the letter before putting it down and crying)
D. have not met (Since leaving university, you and the other person haven't met)