By the time he was twelve he ______ a chemistry lab of his own.
| A．built | B．has built | C．had built | D．was building |
—Why! Where's my passport? Maybe I left it on the plane.
--My Goodness! You ____________ things behind.
| A．had never left | B．didn't leave |
| C．never left | D．haven’t left |
When I tried to find _________that prevented so many people from taking part in the program, it seemed to me that there were two main reasons.
| A．why it did | B．that it did | C．what it was | D．why it was |
Up to Tuesday's attack, the worst school shooting in the U. S. was in March 1998 in Jonesboro,______two boys, aged 11 and 13, shot and killed a teacher and four girls.
| A．while | B．where | C．when | D．then |
—How did you find your visit to the museum, Jane?
--_________.
| A．Oh, wonderful, indeed | B．By taking a number 3 bus |
| C．I went there alone | D．A classmate of mine showed me the way |
_________good, the food was soon sold out.
| A．Tasted | B．Being tasted | C．Tasting | D．Having tasted |