Question

Which sentence has a verb that is in the active voice? In 1854, the ideas behind electronic transmission of human speech had been developed by Charles Bourseul. In 1915, a telephone link between New York City and San Francisco was established by engineers. In 1878, the world’s first commercial telephone company was opened by entrepreneurs in Connecticut. In 1955, engineers placed the first transatlantic telephone cable between Newfoundland, Canada, and Scotland.

Answer 1

The correct answer is:

The sentence which has a verb in the active voice is: In 1955, engineers placed the first transatlantic telephone cable between Newfoundland, Canada, and Scotland.

Whenever a sentence is written in the active voice the subject of the sentence will be performing the action of the verb.

The structure of a sentence in the active voice shall be:

Subject (engineers) + verb (placed) + object (the first transatlantic telephone)

The other three sentences are written in the passive voice. Note that they all follow some of the basic rules applied to passive voice: the object has taken the place of the subject, the use of past participle, and the word "by" used before the subject.

Answer 2

In 1955, engineers placed the first transatlantic telephone cable between Newfoundland, Canada, and Scotland.

This is the only example that employs active voice. A general rule is that the subject is in the first part of the sentences, followed by a verb in simple tense, followed by the object that is receiving the action. In this case, the subject (the engineers) comes first, then the verb which the subject is doing (placed), followed by the recipient object (the telephone cable). 

Notice that all the other examples, the object is introduced first and the verb is described as acting on them by a subject that is later described.