Read the passage given below and answer the questions that follow, by selecting the correct/ most appropriate options :

Which part of the following sentence contains an error ?

He knew
(a) that he will
(b) go back
(c) on his promise
(d) .

Correct Answer: Option (b)

Explanation:

To identify the error in the given sentence, let us analyze its grammatical structure and tense consistency:

"He knew (a) that he will (b) go back (c) on his promise (d) ."

1. The sentence begins with the main clause "He knew", where the verb "knew" is in the simple past tense.

2. According to the rules of sequence of tenses in English grammar, when the main clause (reporting verb) is in the past tense, the verb in the subordinate/dependent clause (introduced by "that") must also be in a past tense form.

3. Here, the modal auxiliary verb "will" is in the present/future form, which violates the sequence of tenses rule. The past tense equivalent of "will" is "would".

4. Therefore, "will" in part (b) should be replaced with "would" to make the sentence grammatically correct: "He knew that he would go back on his promise."

Since the error lies in the usage of "that he will", part (b) is the incorrect part of the sentence.