She acted like she felt sick.其中的“like she felt sick”是名詞子句還是副詞子句?

因為that子句通常不接受「介系詞」的約束（而會將介系詞強制刪去），所以She acted like she felt sick.的like應定位為「連接詞」。like she felt sick是主句述部的「修飾語」，修飾acted的方式，所以是「副詞性質」，而非「名詞性質」。

He behaves the same way I used to.這裡的狀況也是述部的修飾語。the way how通常寫成the way即可，帶出副詞性質的修飾語。所以你也可以說這修飾語是「副詞子句」（依用途定子句的詞性）。

當「受詞」用的「名詞子句」：
I wonder "if he is at home."
Tell me "when she will come back."

但Tell me "when you are ready."是有歧義的句子。當「名詞子句」（當直接受詞）或「副詞子句」（當述部修飾語）解時，意義大不相同。一是：靠訴我，你什麼時候才好。一是：你好的時候，通知我一聲。

She acted.
like=prep---similar in some way to something else:-
very like----eg:-She is very like a sick woman.
look/feel/seem---like:-eg:-
At last she felt like a sick woman, after she acted.
At last she looked like a sick woman.
At last she seemed like a sick woman.

just like---means exactly like-:-eg:-She was just like a sick woman after (she acted).
as if--conjunction--in a way that suggests that something is true or not true
eg:-She looks as if she've had a sick body.
eg:-She felt as if she was feeling sick on herself.
eg:-It sounds as though she's been sick.
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If like=as=an adverb, then adverb clause
Hence;She acted like she felt sick---like she felt sick is an adverb clause of condition.狀態,狀況,情形,外界狀況,她的周圍情形,她旳周遭清況.

想的太複雜了，第一句act 是不及物動詞，不需受詞承接其勯作，而like是介詞，其引導片語當副詞修飾act ,like可以as代替而非as if.
He behaves the same way as I used to. as是準關係代名詞，可以that替代'
介詞後可接單字，片語，子句