1 .The earth _______ on the sun for its heat and light

          A. is depended               B. depends           C. is depending    D. has depended

2. I’m busy at the moment _______on the computer

          A. I work                       B. I’m worked      C. I’m working     D. I worked

3. When I entered the room, everyone _____________.

          A. has been dancing       B. was dancing     C. had danced      D. danced

4. She won't get married until she __________ 25 years old.

          A. is                     B. will be              C. had been                             D. was.

5. This building used to be a library,_________?

          A. doesn't it                   B. didn’t it           C. isn’t it                       D. wasn’t it

6. Nobody was injured in the accident, ________?

          A. was there                   B. was he             C. were they                            D. wasn't it