Which is the subject?

[Federerexpress]

In a sentence like

"I thought the man was eating a pie",

is 'I' the Subject, 'thought' the Verb, and 'the man was eating a pie' a Complement? If so what are the sub parts within this complement?

It's strange because if there wasn't the 'I thought' at the beginning, 'the man' would be the subject, 'was eating' the verb and 'a pie' the object.

Thanks for your help!

[colloquium]

In a sentence like

"I thought the man was eating a pie",

is 'I' the Subject, 'thought' the Verb, and 'the man was eating a pie' a Complement? If so what are the sub parts within this complement?

It's strange because if there wasn't the 'I thought' at the beginning, 'the man' would be the subject, 'was eating' the verb and 'a pie' the object.

Thanks for your help!

I think, as you suspect, the man was eating a pie is a complement, or more specifically a complement clause. It is an argument of the predicate thought; therefore it should be analysed as a clause. The man is the subject of the complement clause.

However I am not sure.

Someone else will be able to give a definate answer.

I am not a teacher.

[Federerexpress]

Thanks for the reply colloquium, it was a good explanation!
One more thing: am I correct in thinking that a clause can only have one subject but a sentence can have more than one subject?

[colloquium]

Thanks for the reply colloquium, it was a good explanation!
One more thing: am I correct in thinking that a clause can only have one subject but a sentence can have more than one subject?

Well a sentence can certainly have more than one subject.

I spoke to richard and he explained the situation to me.

There are clearly two subjects in this sentence: I and he.

I am not sure if a clause can only have one subject.

John and Richard went to the shop. (???)

I'm also not sure if my original answer to your first question is correct.

I wish someone would help!

[Raymott]

Well a sentence can certainly have more than one subject.

I spoke to richard and he explained the situation to me.

There are clearly two subjects in this sentence: I and he.

I am not sure if a clause can only have one subject.

John and Richard went to the shop. (???)

I'm also not sure if my original answer to your first question is correct.

I wish someone would help!

Someone will almost certainly correct you if you're wrong.
The subject of the above sentence is "John and Richard".
A clause has one subject and one main verb.