Primary sources are sometimes difficult to understand because english words:
o
a. have unusual meanings.
b. are hard to spell.
o c. have changed a great deal over time.
o
d. are longer than words in other languages.

C. have changed a great deal over time.

Explanation:

Primary sources are sometimes difficult to understand because English words have changed a great deal over time.

hello,

your answer is a) the metaphor suggests that the poetic themes are serious and dark.

collins is comparing the poem to a dark room. he is suggesting that the poems theme is serious and wants you to understand it. you don't need to understand the poet in order to understand the poem. you also don't need to move around while reading it. he is simply saying the poem has a dark and serious theme.

- i.a -