We will now study the structure of the simple sentence and the types of simple sentences. First of all we shall have to deal with the problem of negative sentences. The problem, briefly stated, is this: do negative sentences constitute a special grammatical type, and if so, what are its grammatical features? In other words, if we say, "This is a negative sentence," do we thereby give it a grammatical description? The difficulty of the problem lies in the peculiarity of negative expressions in Modern English. Let us take two sentences, both negative in meaning: (1) She did not know when she would be seeing any of them again. (R. MACAULAY) (2) Helen's tremendous spell — perhaps no one ever quite escaped from it. (Idem) They are obviously different in their ways of expressing negation. In (1) we see a special form of the predicate verb (did... know, not knew) which is due to the negative character of the sentence and is in so far a grammatical sign of its being negative. In (2), on the other hand, there is no grammatical feature to show that the sentence is negative. Indeed, there is no grammatical difference whatever between the sentences Nobody saw him and Everybody saw him. The difference lies entirely in the meaning of the pronouns functioning as subject, that is to say, it is lexical, not grammatical. The same is of course true of such sentences as I found nobody and I found everybody. On the other hand, in the sentence I did not find anybody there is again a grammatical feature, viz. the form of the predicate verb (did... find, not found). The conclusion to be drawn from these observations is obviously this. Since in a number of cases negative sentences are not characterised as such by any grammatical peculiarities, they are not a grammatical type. They are a logical type, which may or may not be reflected in grammatical structure. Accordingly, the division of sentences into affirmative and negative ought not to be included into their grammatical classification. Before we proceed with our study of sentence structure it will be well to consider the relation between the two notions of sentence and clause. Among different types of sentences treated in a syntactic investigation it is naturally the simple sentence that comes first. It is with specimens of simple sentences that we study such categories as parts of the sentence, main and secondary; homogeneous members, word order, etc. It is also with specimens of simple sentences that we illustrate such notions as declarative, interrogative, imperative, and exclamatory sentences, as two-member and one-member sentences, and so forth. As long as we limit ourselves to the study of simple sentences, the notion of "clause" need not occur at all. When, however, we come to composite sentences (that is, sentences consisting of two or more clauses), we have to deal with the notions of main clause, head clause, and subordinate clause. Everything we said about the simple sentence will also hold good for clauses: a clause also has its parts (main and secondary), it can also be a two-member or a one-member clause; a main clause at least must also be either declarative, interrogative, imperative, or exclamatory, etc. We will consider these questions in due course. So then we will take it for granted that whatever is said about a simple sentence will also apply to an independent clause within a composite sentence. For instance, whatever we say about word order in a simple sentence will also apply to word order in an independent clause within a composite sentence, etc.