Here is the item again:
Belinda hates her psychology class, although her professor is an interesting lecturer, the auditorium is right next to the copy center, and the whump, whump, whump of the machines always makes Belinda drowsy.

The comma between class and although creates a comma splice. At this spot, there are two complete sentences joined with a comma alone, making a major sentence error. Belinda hates her psychology class is the first complete sentence. Although her professor is an interesting lecturer, the auditorium is ... begins the next complete sentence.

To fix this problem, you could put a period after class and capitalize the A for although.

Congratulations! You have finished Exercise 3!

Return Home.

Go to Exercise 4.