怎樣用 each other ？(英文文法)

each other是只是兩人的活動.(放在尾)
one another 是三人或以上的活動.(放在尾)

each other 是三個以上的其中之一
one another 是二個之一^_^

each other 是放在句末
Which 是用來詢問問題

例子:
1. Which colour do you like?
是詢問哪個

1.each other means the other people
2. Which is used at the first of the sentenses

1. We don't have to visit each others in person but we can send the e-mails to each others instead.
2. Which hotel you are staying in Hong Kong?