用适当的介词填空。 1. I was invited _______ Mary's birthday party last week. 2. If you want to go to another country, you should first know _______ the country. 3. There's no s imilar expression _______ 'manman chi' _______ English. 4. _______ the start of a meal, the Chinese like to ask the guest to eat well. 5. Soup is usually eaten _______ a spoon.