Eight dollars (is, are) the price of a movie these days.

"Is" is the verb of this sentence.  Though a subject of a clause is typically in front of the verb, this is an "inverted sentence," meaning that the subject comes after the verb.  If this sentence weren't to be inverted it would read, "The price of a movie (is,are) eight dollars these days."  The verb is describing the word "price" and because "price" is singular, it must have a singular verb meaning the correct verb usage is "is."

both the address and the poster use diction to convey their message. diction is defined as a style of writing or speaking based on the types of words chosen in order to send a message. parallelism is when a similar sentence structure is used for several sentences on a text; roosevelt's address doesn't follow that. repetition has to do with repeating a word or sentence in order to emphasize and idea, however neither the poster nor the address use repetion. finally, the address doesn't use images to convey a message.

greet them:

buenas noches.

that is considered night time which is when "good night" is used.