I won’t call you, __________ something unexpected happens.
It is good manners to eat up _______is left in your plate.
Can you explain ________ the sun goes down in the west?
A huge amount of oil was spilt on the East Sea, the causes of ______ are still under investigation.
--- Has James finished his report on his Enquiry Learning yet?\ ---- I’m not sure. He _____ on it last week.
If you are traveling_ the customs are really foreign to your own,please do as the Romans do.