The structures practiced in this lesson are the ones that are most often tested in the Structure section. About 20% of all problems in the section (usually three or four per test) involve incomplete independent clauses.
All sentences consist of one or more clauses. A simple sentence consists of one clause.
People need vitamins.
The man took a vitamin pill.
Judy lives in northern California.
In the summer, Tom walks to his office.
A compound sentence consists of two independent clauses joined by a coordinating conjunction (such as and and but).
The man took a vitamin pill, and he drank a glass of orange juice.
Judy lives in northern California now, but she was raised in Ohio.
A complex sentence consists of an independent clause (called the main clause) and a dependent (subordinate) clause. Subordinate clauses may be adverb clauses, noun clauses, or adjective clauses. In the sentences below, the independent clauses are italicized.
The man took a vitamin pill because he had a cold.
(independent clause+ adverb clause)
I didn’t realize that Nancy was here.
(independent clause+ noun clause)
Tom walks to his office, which is located on Broadway, every day during the summer.
(independent clause+ adjective clause)
All three types of subordinate clauses are commonly seen in the Structure part of the test, and each is considered in separate lessons (Lessons 18, 21, and 22). The emphasis in this chapter, however, is on the basic components of independent clauses.
All clauses have a subject and a verb. Clauses with an action verb often take a direct object as well.
| Subject | Verb | Object |
| People | need | vitamins. |
The verb missing from an independent clause may be a single-word verb (need, was, took, had, walked) or a verb phrase consisting of one or more auxiliary verbs and a main verb (will need, has been, should take, would have had, had walked). The verbs may be active (need, take) or passive (was needed, is taken).
The missing subject and direct object may be a noun (people, vitamins, Tom), a noun phrase (some famous people, a vitamin pill, my friend Tom), or a pronoun. (He, she, it, and they are subject pronouns; him, her, it and them are object pronouns.)
After the verb to be and certain other non-action verbs, a subject complement is used rather than a direct object. (Subject complements are also known as predicate nominatives and predicate adjectives.)
| Subject | Verb | Complement |
| She The teacher | is seemed | an architect. upset. |
In the Structure section of TOEFL, it is common for any of these elements or a combination of two or more of these elements to be missing from the stem. The most common problem in Structure involves a missing verb. A missing subject and a missing subject-verb combination are common as well. The missing element may also be part of rather than all of the verb or noun phrase.
∇ Sample Item
The art of storytelling ________________ almost as old as humanity.
(A) that is
(B) is
(C) it is
(D) being
The correct answer (B) supplies the missing verb. Choice (A) is incorrect because the word that is used to connect a relative clause to a main clause; in this sentence, there is only one verb, so there can only be one clause. Choice (C) is incorrect because there is an unnecessary repetition of the subject (The art of storytelling it . . .). Choice (D) is not correct because an -ing form (being) cannot be the main verb of a clause.
______________ a few of the sounds produced by insects can be heard by humans.
(A) Only
(B) There are only
(C) That only
(D) With only
The correct answer (A) completes the noun phrase that is the subject of the sentence. The expletive There in choice (B) is incorrectly used. In (C), the word That creates a noun clause, but each clause must have its own verb. (Produced is used as a participle, not a main verb, in this sentence.) Choice (D) is incorrect because a preposition may not be used directly before the subject.
______________ when lava cools very rapidly.
(A) Because pumice is formed
(B) To form pumice
(C) Pumice is formed
(D) Forming pumice
The best answer supplies an independent clause to join to the adverb clause when lava cools very rapidly. Choice (A) consists of an adverb clause; two adverb clauses cannot be joined to form a complete sentence. Choices (B) and (D) are incorrect because they do not contain main verbs, and an independent clause must contain a main verb. (To form and forming are not main verbs.) Only choice (C) could serve as an independent clause because it contains a subject (Pumice) and a full verb, the passive verb is formed.
Duke Ellington wrote ________________ during his career.
(A) that over a thousand songs
(B) over a thousand songs
(C) over a thousand songs were
(D) there were over a thousand songs
The direct object is missing from this sentence. In choice (A), the connecting word that is used unnecessarily. In (C), the verb were is used unnecessarily because there is only one clause and it has a verb (wrote). In choice (D) the phrase there were is not needed between a verb and its direct object. Choice (B) correctly supplies a noun phrase that serves as the direct object.
Before the invention of the printing press, books ________________ .
(A) that were very rare
(B) were very rarely
(C) were very rare
(D) as very rare
Choice (A) incorrectly forms an adjective clause; an adjective must be joined to a main clause. Choice (B) contains an adverb; after the verb to be, an adjective is required. Choice (D) lacks a verb. Choice (C) correctly supplies a verb (were).
Some clauses begin with the introductory words there or it rather than with the subject of the sentence. These introductory words are sometimes called expletives.
The expletive there shows that someone or something exists, usually at a particular time or place. These sentences generally follow the pattern there + verb to be + subject:
There are many skyscrapers in New York City.
There was a good movie on television last night.
The expletive it is used in a number of different situations and patterns:
It is important to be punctual for appointments.
(with the verb to be + adjective + infinitive)
It was in 1959 that Alaska became a state.
(with the verb to be + adverbial + noun clause)
It takes a long time to learn a language.
(with the verb to take + time phrase + infinitive)
It was David who did most of the work.
(with the verb to be + noun + relative clause)
It and there, along with the verb and other sentence elements, may be missing from the stem.
∇ Sample Item
In Michigan, ________________ over six hundred feet deep.
(A) salt deposits
(B) where salt deposits are
(C) having salt deposits
(D) there are salt deposits
Choice (D) correctly supplies an introductory word (there), a verb, and a subject. Choice (A) lacks a verb. Choice (B) contains a subordinator, used to introduce a clause; there is only one verb, however, so there can only be one clause. Choice (C) also lacks a main verb.
______________ a tomato plant from 75 to 85 days to develop into a mature plant with ripe fruit.
(A) It takes
(B) To take
(C) That takes
(D) By taking
Choice (A) correctly completes the sentence with the introductory word It and a verb. Choice (B) and (D) do not supply main verbs. Choice (C) incorrectly creates a noun clause.