In many cities of China, if an ambulance is__in a traffic jam, police will respond to the emergency.
It suddenly _____ to the detective that the professor was probably murdered by his own wife .
---What made her unhappy? ---_____.
The machine might break down someday in the future, ____, you can dial this number for help.
_________ returns first will win the big prize.
—Mary said Leo worked really hard. — _______.