Select the transitional device that best matches the sentence.
She could not sleep, and ____ she is tired today.
Correct answer: Either can be used.
Explanation: Either can be used to indicate a consequence. However, “therefore” can also be used to denote a logical thread of thought, and its placement in a sentence can be more varied.
Tip for ESL writers: Many writers are tempted to place “Therefore” at the beginning of a sentence; however, these sentences often flow better if this word is used later on in the sentence, as in the examples below. (Note that this also applies to “Thus”.)
Correct example of the use of “as a result”:
Chris has been trained to evade lie-detection systems. As a result, he is also adept at controlling his facial expressions, bodily gestures, and speech.
Correct examples of the use of “therefore”:
Chris found that he could not convince the investigator of his innocence. He therefore had to blow his cover and ask his superior to contact the investigator.
We could not find any apples or bananas at the shops. We purchased double the quantity of pears and peaches, therefore, to ensure that there would be enough fruit for everyone.