What is the correct contraction for "will not"?

The contraction "they're" combines the pronoun "they" with the verb "are." It is a shortened form used to represent the combined words in a more concise and informal manner. The apostrophe in "they're" replaces the missing letter "a" from "are."

The other options are not the correct contractions for "they are."

Option A, "their," is a possessive pronoun indicating ownership. It is not a contraction for "they are."

Option B, "the're," is not a valid contraction in English. The correct form is "they're."

Option D, "No Contraction used," is not the correct answer because "they're" is the appropriate contraction for "they are."

Therefore, the correct contraction for "they are" is "C. They're."

The correct sentence would be: "The shopper was angry when he realized he could have gotten it cheaper at the other store."

The phrase "could have gotten" is the correct past participle form of the verb "get" to express a possibility or potential action that didn't happen in the past. The other options (A, C, and D) do not use the correct verb form or structure to convey the intended meaning in this context.

This sentence uses the correct form of the verb "to have" after the preposition "to." In this case, the infinitive form "to have" is used correctly to express anticipation or expectation. The phrase "having my birthday party" is a gerund phrase, which functions as the object of the preposition "to" and correctly conveys the action of the birthday party taking place in the future.

The other options contain incorrect verb forms or structures:

B. "I am looking forward to go my birthday party next week." - The verb form "go" is incorrect after the preposition "to." It should be "going."

C. "I am looking forward to going my birthday party next week." - The sentence is grammatically incorrect as it lacks the preposition "to" before "my birthday party." The correct form would be "looking forward to going to my birthday party."

D. "I am looking forward to have my birthday party next week." - Similar to option B, the verb form "have" is incorrect after the preposition "to." It should be "having."

Therefore, option A is the correct and grammatically sound sentence.

The teacher and the student knew that he was wrong.

In this sentence, there is an issue with pronoun agreement. The pronoun "he" does not agree in number with the plural subject "the teacher and the student."

To correct the sentence, you could say: "The teacher and the student knew that they were wrong." Here, the plural pronoun "they" agrees with the plural subject.

Therefore, option B is the sentence that is not grammatically correct due to pronoun agreement.