Sentences with adverb clauses have two basic patterns in English. Study the clauses and connectors in the following sentences:
He is tired because he has been working so hard.
Because he has been working so hard, he is tired.
In each of these examples, there are two clauses: he is tired and he has been working so hard. The clause he has been working so hard is an adverb clause that is introduced with the connector because. In the first example, the connector because comes in the middle of the sentence, and no comma (,) is used. In the second example, the connector because comes at the beginning of the sentence. In this pattern, when the connector comes at the beginning of the sentence, a comma (,) is required in the middle of the sentence.
The following example shows how this sentence pattern could be tested in the Structure section of the TOEFL test.
_____ arrived at the library, he started to work immediately.
(A) The student
(D) After the student
In this example, you should recognize easily that the verb arrived needs a subject. There is also another clause, he started to work immediately. If you choose answer (A) or answer (C), you will have a subject for the verb arrived, but you will not have a connector to join the two clauses. Because you need a connector to join two clauses, answers (A) and (C) are incorrect. Answer (B) is incorrect because there is no subject for the verb arrived. Answer (D) is the best answer because there is a subject, student, for the verb, arrived, and there is a connector, after, to join the two clauses.
The following chart lists common adverb connectors and the sentence patterns used with them.
EXERCISE 6: Each of the following sentences contains more than one clause. Underline the subjects once and the verbs twice. Circle the connectors. Then indicate if the sentences are correct (C) or incorrect (I).
1. After the plane circled the airport, it landed on the main runway. (C)
Both clauses have subject and verb.
The connector “when” is correct, too.
2. The registration process took many hours since the lines so long. (I)
The second clause has no verb. It should be the lines were so long.
The connector “since” is correct.
3. This type of medicine can be helpful, it can also have some bad side effects. (I)
Both clauses are correct but there is no connector.
4. The waves were amazingly high when the storm hit the coastal town. (C)
Both clauses and connector are correct.
5. We need to get a new car whether is on sale or not. (I)
Second clause has no subject. It should be it is on sale or not
Connector “whether” is correct
6. Just as the bread came out of the oven, while a wonderful aroma filled the kitchen. (I)
There are two connectors; Just and While.
“While” should be erased, so the sentence becomes a wonderful aroma filled the kitchen.
7. Everyone has spent time unpacking boxes since the family moved into the new house. (C)
Both clauses and connector are corretc.
8. Although the area is a desert many plants bloom there in the springtime. (I)
There is no comma after the first clause. It should be the area is a desser,
9. The drivers on the freeway drove slowly and carefully while the rain was falling heavily because they did not want to have an accident. (C)
All three clauses are correct and the connectors are correct, too.
10. If you plan carefully before you take a trip, will have a much better time because the small details will not cause problems. (I)
Second clause ” will have a much better time” has no subject. It should be you will have a much better time.