Beijing or Peking?
You might get a little confused about the difference between Beijing and Peking. Is it Beijing duck or Peking duck, Beijing opera or Peking opera? Unfortunately, people use both terms and each side seems to think they are the most correct. The Chinese name of the capital city didn't change, just the romanized spelling. In my view, Peking is just a wrong spelling that became popularized. The city's name is pronounced 北京 and should be spelt in English with a "B". However, the name Peking was used for many years and it stuck. Some people insist on using "Peking" because that's what they think foreigners are used to. Others use Beijing for the city name, but keep Peking for well-known names like Peking duck or even Peking University. Regardless, you can use either Peking or Beijing, but at least in my view, Beijing is preferable.
（例）你们住在哪儿？Where do you live?
（例） 你从哪儿来？Where do you come from?
（例） 哪儿卖火车票？Where do they sell train tickets?
2）给 preposition, as in "for" somebody
（例）妈妈给儿子收拾房间。The mother tidied the room for her son.
（例）他给我介绍了中国的交通情况。He told me all about the Chinese transportation.
3）应该 should do something or be some way
If he took the 2 o'clock train, he should have arrived by now.
He grew up in China, he should understand Chinese.
It's already March, it should be warm by now.
4）可以……can, possibly, maybe
Can I use this telephone?
Substitution and Extention
2）V + 一下儿