Choose the alternative that best completes the blanks in the text, following 1 to 4 order. 
If we add the prefix -UN to some words in English, we can get the opposite of that word, like in unwanted (l. 29). In this sense, consider the following words and analyze them:
I. able.
II. happy.
III. fair.
IV. acceptable.
Which of them can be an opposite just by adding the prefix -UN?
Choose the alternative that presents a synonym to the underlined word in the context below:
But with practice you can learn to disrupt and tame negative cycles. (l. 13).
The sentence But constant negativity can also get in the way of happiness, add to our stress and worry level and ultimately damage our health.' (l. 02-04) could be paraphrased only by the following: 
The word help (l. 17) may be both a noun and a verb without having to change its spelling. The same may occur to all the words bellow, EXCEPT for: 
In the sentence taken from the text: The ability to recognize hand poses, for instance, will make it possible for people to interact with computers in new and more natural ways, such as communicating with computers simply by pointing at things, the underlined expression introduces: 
Segundo o texto, as relações entre Estados Unidos e Cuba
Segundo o depoimento da iraniana Sahar Zand, 
Na letra da canção Hey You , da banda Pink Floyd, o interlocutor (you) é
O assunto principal do texto NÃO envolve questões relacionadas à 