The number of the subject determines the number of the verb

Strunk & White's Elementary Rule of Usage No. 9: The number of the subject determines the number of the verb.
Words that intervene between subject and verb do not affect the number of the verb.

NO The bittersweet flavor of youth--its trials, its joys, its adventures, its challenges--are not soon forgotten.

YES The bittersweet flavor of youth--its trials, its joys, its adventures, its challenges--is not soon forgotten.


Try this SAT Question of the Day:

One of Francisco Goya’s
portraits of Carlos II
A
show the king in hunting attire,
B
with a rifle in his left hand,
C
gloves in his right, and a hunting dog
asleep at his feet.
D
No error
E