In the sentence "Carlos played football", you can recognize "Carlos" as the express subject.
In the field of grammar , the noun phrase, pronoun or noun that agrees in number and person with the verb is called a subject . A subject is a verbal argument : a constituent or complement that is obligatorily required by a verb.
There are various mechanisms to recognize the subject of a sentence . When phonetic criteria are considered, the subject that is explicitly mentioned in the sentence is called the express subject .
For example: “Carlos played soccer.” In this case, the sentence has an express subject ( “Carlos” ). We can ask ourselves “who played soccer?” and thus separate the sentence into subject and predicate: “Carlos” (express subject) “played football” (predicate).
Express subject vs. tacit subject
To all of the above we must also add the fact that the express subject that concerns us has the particularity that it has a noun phrase that allows it to be placed anywhere in the sentence. However, we cannot deny that it is usually at the beginning of it.
If the subject does not have an explicit phonetic realization in the sentence, it is called a tacit subject or elliptical subject : “I played soccer.” As you can see, in this sentence there is no express subject, but it can refer to different people: “I played soccer,” “You played soccer,” “She played soccer,” “He played soccer.” . On the other hand, the expression “Carlos played soccer” makes the subject explicit.
In the same way, we can highlight that this other type of subject is also called the implicit subject. The express subject, in short, is the most frequent since it leaves no room for doubt. It is always clearer to construct sentences with an express subject than to appeal to a tacit subject.
The express subject is the most common.
Other classifications
However, we cannot ignore that there are also other types of subjects. Thus, for example, there is what is known as the simple subject and also the compound subject. The simple cited is one that is characterized by having a single nucleus, which means it can be either a noun or a pronoun. An example would be the following sentence: “Manuel is a great soccer player.” In this case, the subject is directly Manuel.
When we talk about a compound subject, on the other hand and as can be imagined, it is one that has two or more nuclei. Thus, a clear example would be “Luis and Eva have spent the entire afternoon playing ball.” Luis and Eva are the composite subject because they are the ones who carry out the action of having had fun with the ball.
And there is also the indeterminate subject, which is one that stands out for being unknown. A clear example is: “The grocery store next to my house has been robbed.”