Difficulty understanding

This is a real challenge, and part of the answer is that non native speakers really are at a nontrivial disadvantage. However, non native speakers can and do score very high! I think there are a few things I would note. First, you want to get your English reading ability as strong as possible. This feels fairly obvious but I think it does bear repeating. I think that just reading a lot of English texts is truly helpful for the test. Doesn't really matter what you read, fiction, nonfiction, whatever- reading skills build on themselves. Second, I would review the active reading materials, and try to actively translate the ideas expressed in the test. This is actually something that I recommend all test takers do: it will almost always be easier to think about your understanding of an idea than to use the clunky language of the test. By this I mean reading and understanding the text carefully, and then simplifying it for myself. So, I might translate the first sentence to mean "the fact that another country can wipe you out makes you less likely to attack that country." This captures the essence of the statement but is way easier to understand. I think that this sort of active reading and rephrasing is a great way to retain and understand where the phrasing is weird or unfamiliar.