The Sanlu Milk Powder event is a clear indication that food safety is a big problem; nobody can ___ all foods are secure to us, but we are sure that the situation is turning for the better.
_____ the football game will be held on time largely depends on the weather.
– How long _____ in this job? – Since 1990.
I regret _____ more time with my grandma before she passed away.
The film was set in a town _____ is now part of Jiangsu Province.
Though _____ with different medicines, the patient hasn’t recovered from the mysterious illness yet.