On snowy days, you have to drive very ________ to avoid traffic accident.

Up to now, Hope Project has helped thousands of students who would       have dropped out of school.

In a sense, no country, big or small, should object to the trend of peace and development, ______ creating trouble to others.

Mrs Black isn’t in and I’ll have to ring ______. I would appreciate it if you ring _____ after 6 o'clock?  

On foggy days, you have to drive very ________ on the expressway to avoid traffic accidents.