Every predicate in English possesses predicative (personal) form of the verb. This form may be presented explicatory (not zero) and by zero variant. Predicative form in the predicate may belong both to notional and functional verb.
When Predicate is expressed by notional verb it is called Simple. (John smiled. Bill ran away quickly.) Simple Predicate also includes predicates expressed by notional verbs in their analytical forms. (John has come. Bill is reading a book.)
This type of Predicate is considered simple because at syntactic level analytical form of the verb is considered as unity.
If predicative form belongs not to a notional verb but to a functional one (but not in cases of analytical forms) then we can speak about Complex Predicate. These cases include usage of the verb 'to be' as a link verb or copula (Nominal Predicate) or one of modal verbs (Complex Predicate). Sometimes after modal verb infinitive of the link verb 'to be' is used. (Bill may be angry with me). This is Complex Nominal Predicate.
An opposition to Complex Nominal Predicate when modal verb introduces infinitive of notional verb (including its analytical form) is called Complex Verbal Predicate.
Simple Predicate. In Simple Predicate there is always predicative (analytical and simple) form of the notional verb. But it doesn't mean that simple predicate is equal to predicative form of the verb. If predicate is presented by not a simple verb but by a whole word-combination, then predicative form represents only the nucleus of the predicate (in case of subordinative phrase) or one of IC of the predicate (in case of coordinative phrase).
'She sat with her hands nervously clasped'.
'We not only saw but heard it'.
Nominal Predicate. The obligatory part of nominal predicate is a link verb, the purpose of which is expression of mood, tense, and other categories of the words which do not have these formants.
Construction 'is A/N; was A/N' is predicate where grammar indicators are expressed by a functional verb 'to be', while lexical meaning is expressed by non-verbal element (nominal) elements of the structure. So in Nominal Predicate deviation of functions takes place while in a Simple Verbal Predicate both functions are carried out by a notional verb.
The evidence that 'to be' being a functional verb is the fact that it fails to include in its set of forms the verb 'to do'.
The nominal predicate in English may have the following structure
be N is a teacher
be.ANP is a good teacher
be A is angry
be AP is angry with me
be Q is sixteen
be In is nothing
be DP is out
be la is here
and others
Complex Predicate. The Link Nominal and Verbal Complex Predicate has a functional verb as its centre, but it is not a link verb but one of modal verbs:'
can/could, may/ might, must, shall/should, will/would, ought, used — are constant modal verbs
dare — facultative modal verb
need — modal verb in certain constructions
be — modal equivalent.
They have the following formal peculiarities:
a) the absence of suffix -s in the 3-rd person singular present tense.
b) the absence of non predicative forms.
Modal verbs in English are used only in the composition of a predicate. Forms of M.V. are limited to the forms connected with syntactic function of Predicate (simple Tense forms and Mood forms). Forms of Past Tense and of Subjunctive Mood are homonymous and are often difficult to distinguish.
The same modal verbs (must, ought, need, used) have only one unchangeable form.
Subject
The only criterion for definition of Subject in English is its correspondence with Predicate (because of the absence of the formal nominative).
Word order also participating in distinguishing of Subject can not be considered a reliable criterion because of often cases of inversion.
In syntactic function of Subject in English can be used:
a) noun and substantivized word-combinations
"Dinner will be ready in a few minutes";
b) Substantivized pronouns
"He loved her with a deep calm love";
c) Infinitive and phrases with Infinitive as nuclei [nju:kliai]
"To see him is always a pleasure";
d) Gerund and phrases with Gerund as nuclei [nju:kliai]
"Being out in a boat on the river makes you feel healthy and happy";
e) Infinitive predicative phrases
"For you to go there would mean to participate in all that fuss";
f) Gerund predicative phrases
"His having been in business made all the affair meaningless".
COMPLEX SUBJECT