カンマの用法について
Having picked out this one general point, it is hard to select others for special mention here because there are so many equally good candidates - the fact that two equally normal, bright children may start speaking at different ages, the fact 20 that children may know' adult forms but use different ones themselves and so on and on.
この文章の,bright〜, は挿入なのですか？ その場合同格のthatの後は完全文ではなくてもよろしいのでしょうか
回答
挿入されているものはありません。because の後だけ説明します。
There are so many equally good candidates.
ハイフンの後、次のような事柄を例として挙げています。
(1) two equally normal, bright children may start speaking at different ages.
(2) children may know adult forms but use different ones themselves
(3) and so on and on.
たぶん、「bright」の前のコンマにつまずいたのだろうと察します。「and」の代わりによく使います。会話では短いポーズを入れて発音します。
Who does not like kind, smart people?
Did you see a tall, blond woman in the parking lot?
I used to carry an old, brown bag to my office.