The subject of a sentence describes the person or thing being discussed by the sentence. The easiest way to identify the subject is to look for the verb in the sentence and ask who or what is doing it. For instance, in the sentence "We walked down the street together," the subject of the sentence is "we." In certain cases, the subject of the sentence is only implied. For instance, in an imperative sentence such as "Pick up that paper," the subject "you" isn't stated.
While the subject identifies what the sentence is about, the predicate tells the reader about that person, thing or concept. The predicate includes a verb and often other words that modify the verb. For instance, in the sentence "He runs," the predicate is simply a verb, "runs." In the sentence "He runs down the street," however, the predicate --- "runs down the street" --- is longer and contains more information about the verb. A compound predicate contains more than one verb, as in the sentence "She sings and dances."
English grammarians sometimes prefer to separate the predicate into a verb and an object. The object is a noun that's affected by the verb in the predicate. For example, in the sentence "He drove the car," "he" is the subject, "drove" is the verb and "the car" is the object. However, not all sentences have objects. Another part of both subjects and predicates is the complement, a word that modifies either the subject or object. For example, in the sentence "He seems unwell," the complement "unwell" modifies the subject "he."
Often, the subject appears first and the predicate second in a sentence. However, this isn't always the case. For instance, in interrogative sentences, the order of subject and verb is often reversed. For example, a declarative sentence might begin with its subject, as in the sentence "The store was open." However, if the sentence were to be turned into a question, the order would be reversed: "Was the store open?" "The store" is still the subject, even though it doesn't appear first in the sentence.