1. 两个；两个都
You use both when you are referring to two people or things and saying that something is true about each of them.
2. 不仅…而且…；…和…都；既…又…
You use the structure both...and when you are giving two facts or alternatives and emphasizing that each of them is true or possible.
Notice that all these sentences mean the same thing:
Both boys have been ill', '
Both the boys have been ill', '
Both of the boys have been ill', '
The boys have both been ill'. You cannot say '
Both of boys have been ill', although when a pronoun is used, you can say '
Both of them have been ill'. See also note at
all.
注意以下各句含义相同：
Both boys have been ill,
Both the boys have been ill,
Both of the boys have been ill, The boys have
both been ill（两个男孩都病了）。不能用
Both of boys have been ill，但在和代词一起使用时可以说
Both of them have been ill（他们两个都病了）。亦见all词条下的说明。
