Lesson 125 Partying with foreign

Partying is fun.But have you ever been invited to a party by a foreigner?What shoud you wear?Shoud you bring anything?If so,what?Don't worry.Today we are going to give you some tips about partying with foreigners.
First,you should ask if it is a normal or casual party.then you will know what to wear.It's as simple as that.At a casual party.It's customary to bring a bottle of wine or some other refreshment.It is not considered polite to bring someone along with you unless you first ask your host.At more formal parties like birthdays,a small gife will be sufficient.Giving money would cause some embarrassment.Finally,never overstay your welcome.When it's getting late,It's time to thank your host for a wonderful evening and say good night.

whether/if 不可通用得情况，是做介词宾语时不可互换