The book, ________ he lost yesterday, ________.
Modern teaching equipment as well as tens of computers _______ to the village school last week.
The number of air crashes that _______ in developing countries _________ increasing.
Bill suggested ________ a meeting on what to do for the Shanghai Expo during the vacation.
_________many times, he finally understood it.
This morning, I rushed to the library, only ________ that its door was still locked.