16. Two students are ------------------------- their professor about the possibility of obtaining a good grade in class.

Answer: A

Explanation:

Two students are asking their professor about the possibility of obtaining a good grade in class.

The sentence properly conveys that the students are currently in the process of inquiring about their academic performance, making "asking" the most appropriate choice.

A) Asking

This option accurately reflects the present action being performed by the students. The use of "asking" indicates that the students are actively engaging with their professor to seek information regarding their grades.

B) Is

This option does not fit the context of the sentence, as "is" lacks a subject and verb structure that conveys an action. It does not provide any information about what the students are doing concerning their professor.

C) Was

Choosing "was" would imply that the action of inquiring occurred in the past. This contradicts the present tense implied by the structure of the sentence, making it an inappropriate choice.

D) Could

The word "could" suggests a possibility or ability rather than an action being taken. It fails to convey the direct action the students are undertaking, which is necessary for the sentence to make sense.

Conclusion

The correct answer, "asking," clearly captures the active inquiry of the students in the present moment. All other options fail to reflect this ongoing action, either by lacking context or by incorrectly situating the action in the past or as a passive possibility. Therefore, "asking" is the definitive choice that maintains the intended meaning of the sentence.