Question

Which sentence has an error in subject-verb agreement? The importance of Fleming's discovery wasn't realized right away. It wasn't until about 1940 that penicillin became widely used in medicine. Since then, penicillin has cured some diseases that once killed millions of people. Fleming was very lucky. But he wouldn't have succeeded if he hadn't been working hard on experiments anyway. His discoveries was a combination of luck and hard work.

Answer 1

The sentence that has an error in subject-verb agreement is:

His discoveries was a combination of luck and hard work.

Step-by-step explanation:

When we say a subject and a verb have to agree, we mean the verb must be inflected in accordance to the subject. If the subject is singular, the verb must also be singular. If the subject is plural, the verb is also plural. The verb "to be", especially, is quite an irregular verb, and requires due attention.

Having that in mind, we can say the sentence that contains an error is "His discoveries was a combination of luck and hard work." The noun "discoveries" is the main word of the subject, and it is plural. However, the verb "was" (past form of the verb "to be") can only be used for singular subjects. For the sentence to be correct, it should be:

His discoveries were a combination of luck and hard work.