The government has taken some measures to solve the shortage of water, but it may be some time __ the situation improves.
Attention, please. The plane to London _______ off at 9: 00.
The Spring Festival falls ________ the first day of the Chinese Lunar year.
Do you still remember the chicken farm _____ we visited the other day?
It is diving _____ great speed that often causes serious accidents.
______ is necessary for everyone to obey the traffic rules.