As far as Sentence Construction is concerned, there are two main types of sentence. In this section, we will look at simple sentences, those that only have one verb. In Complex Sentences, we look at the other cases. It is important to realize that this is a quick fix which aims to cover the basics: there are exceptions to many of the general statements that follow. Your grammar book will give more details.
It's useful to think of sentences as built of basic blocks. (The technical term for block in this sense is phrase.) The minimum number of blocks in standard written texts is two, a noun phrase and a verb phrase:
Each phrase can be big or small. You can expand a noun phrase by adding Determiners, Adjectives and also other noun phrases:
You can also contract a noun phrase by using a pronoun:
The noun phrase in the above examples, indicating who or what was doing something, is called the subject and is usually placed before the verb in the sentence in both English and French.
Notice that the term Verb covers various things. Usually, only Conjugated Forms of the verb combine with subjects to form sentences, as in the examples above.
Conjugated Forms are the ones that change according to the subject (il vient, ils viennent, vous venez). Infinitives and participles, although they are also verbs, are Non-conjugated Forms of the verb. It is very important to distinguish between conjugated and non-conjugated forms, because finding the conjugated forms is always the first step in any analysis of a text. You find the conjugated verbs, then look for the subject of each, then the object of each. If there's no verb, there's no subject or object.
Another sort of noun phrase is called an object. It indicates who or what is affected by whatever the subject and verb are doing, and it usually comes after the verb.
In the second sentence there is a direct object (a mouse) and an indirect object (to its young). Both refer to things that are affected by what the snake is doing. You can tell what the direct object of a verb is by asking a what/who? question using the subject and the verb: The snake fed what? = a mouse; Snakes eat what? = mice. An indirect object is normally preceded by a preposition (to its young, de mon ami...)
All of these noun phrases can be contracted to pronouns: It fed it to them.
Finally, a third type of noun phrase indicates when or how
or why or more generally in what circumstances the
action took place. These phrases are called Adverbials and they
can go anywhere in the sentence:
Do not confuse adverbials and Adverbs. Adverb refers to the type of word. Adverbial refers to the job a word or group of words does in the sentence. Adverbs are often used as adverbials, but they can do other jobs too. In the following sentences, all the red words are adverbials, but only two are adverbs:
So we have, apart from the verb, four sorts of blocks or phrases in
simple sentences: subjects, direct objects, indirect objects and adverbials.
All of these phrases can be expanded in various ways to make very complex sentences. In Complex Sentences, you can see how you can add a whole sentence to a phrase (The snakes // that I saw at the zoo // were eating mice). But (with some exceptions: see Predicates) all sentences can be divided up into the four types of blocks: subjects, objects, adverbials and verbs.
When trying to understand a sentence, it is often useful to know which block words belong to. Word order is not always a good guide: the subject might come after the verb, or the object before it. You usually assign words to the right block intuitively, but if the word order is different in French, as it sometimes is, you may have to work at it a little.