Here, the prefix "un-" applied to the word "common" results in the word "uncommon," which means the opposite of common. Something that is uncommon is therefore "rare." 

Given that "uncommon" and "rare" mean the same thing, the correct answer choice will be one in which the two words also mean the same thing. Something that is "spontaneous" is not planned. Therefore, the answer choice "unplanned is to spontaneous" is the correct answer.

The prefix “tele-“ means over a long distance, so a “telephone” is a device that you use to call over a long distance and a “telescope” is a device that you used to see over a long distance. Notice how the root “phone” means having to do with a device that relates to sound, as in “megaphone” or “gramophone,” and the root “scope” means having to do with a device that relates to seeing, as in “microscope” or “periscope.”

To solve this analogy, you have to understand the meaning of the prefixes "un-" and "dis-." Both prefixes are used to negate the meaning of a word. They take the original meaning and make it the opposite, so "unpleasant" means not pleasant. "Nice" is the opposite of "unpleasant," so to solve this analogy, you need to find the opposite of "dishonest." "Dishonest" means not honest, so the correct answer must mean something like "honest." The correct answer is therefore "truthful." To provide further help, "terrifying" means scary, and "serene" means peaceful.

This analogy requires you to use your knowledge of negating prefixes. "Un-" and "dis-" both mean not; they each take the meaning of the original word and make it mean the opposite. So "disconnected" means not connected. "Separated" is very similar to this meaning, so to solve this analogy, you have to find a word that is similar in meaning to "unfulfilled." "Unfulfilled" means not fulfilled or not satisfied, so the correct answer is "dissatisfied." To provide further help, "misplaced" means lost, "misunderstood" means incorrectly understood, and "satisfied" means happy with something.

"Loyal" is an antonym of "disloyal," so you need to pick out an answer choice that is an opposite of "dull." "Dull" can mean either boring or not sharp, so "exciting" is the correct answer, because "exciting" is an opposite of "boring." To help you, "munificent" means generous; and "guilty" means feeling bad about something bad that you did.

To solve this analogy you have to rely on you understanding of prefixes. The prefix post- means after, so to "postpone" something is to delay something to be done later. To solve this analogy then you have to determine which one of these words is something that you do "before" something else. The prefix pre- means before, so the correct answer is "prevent." "Prevent" means to stop something from happening before it happens. To provide further help, "permit" means to allow; "determine" means to figure out.

To solve this analogy you are going to need to rely on your understanding of prefixes. The prefix psych- means mind, to do with the human mind. So, "psychology" is the study of the mind. To solve this analogy then you have to determine what "astronomy" is, to do this you need to use the prefix astro-, which means star, or space. "Astronomy" is the study of stars and outer space.

The prefix oct- means eight, so an "octagon" is a shape with eight sides. To solve this analogy you need to consider the meaning of the prefix tri-. It means three. So, a "triangle" is a shape with three sides.

To be "starving" means to be very hungry, to need food. So, if you are "starving" you need food. To solve this analogy you need to determine what it is that you need when you are "dehydrated." To do this it helps to consider the roots of the word "dehydrated." -hydra- means water. To be "dehydrated" means to be very thirsty, to need water.