(     )1. A. When was the calculator invented?
           B. When was the computer invented?
           C. When was the telephone invented?
(     )2. A. I think it was invented in 1876.
           B. I think it was invented in 1877.
           C. I think it was invented in 1867.
(     )3. A. What do you think is the most helpful invention? 
           B. What do you think is the most useful invention?
           C. What do you think is the most helpful invention?
(     )4. A. By the time he went into the classroom, the class had been cleaned.
           B. By the time he went into the classroom, the class had finished.
           C. By the time he went into the classroom, the class had begun.
(     )5. A. What happened to David on April Fool's Day?
           B. What happened to Tom on April Fool's Day?
           C. What happened to Danny on April Fool's Day?