Select the word or phrase that makes this sentence grammatically correct.

The shopper was angry when he realized he------ it cheaper at the other store.

The verb "ran" is used correctly in its past tense form to indicate the action of moving quickly on foot.

The correct preposition to use in this context is "if" instead of "by."

Therefore, the corrected sentence would be: "Confidentiality should be observed at all times, so the nurse should not discuss clients when the conversation can be overheard by others."

The options A. "should not," B. "be observed," and C. "can be" are used correctly in the sentence. It is only the incorrect use of "By" that makes the sentence grammatically incorrect

"The men and women of the graduating class threw their caps into the air."

In this sentence, "threw" is the past tense of the verb "throw" and matches the subject "The men and women of the graduating class" in terms of verb agreement. It indicates that the action of throwing the caps into the air was performed by the graduating class.

The other options do not fit the context:

A. "Thorough" is an adjective that means complete or careful. It does not fit the action of throwing caps.

C. "Throwing" is a present participle form of the verb "throw" and does not match the tense needed in the sentence.

D. "Through" is a preposition that indicates movement or passage, but it does not fit the action of throwing caps.

Therefore, the correct word to make the sentence grammatically correct is B. "Threw."

The correct term to use in this context is "capital" instead of "capitol."

"Capital" refers to an uppercase letter, which is used at the beginning of a sentence. On the other hand, "capitol" typically refers to a building that houses a legislative body. In the given sentence, the intended meaning is about the rule of using uppercase letters, not the physical building.

Therefore, the corrected sentence would be: "A sentence must always begin with a capital letter, but many people forget this simple rule."

The options B. "Forget," C. "Simple," and D. "must always" are used correctly in the sentence. It is only the incorrect use of "Capitol" that makes the sentence grammatically incorrect.