According to the Institute of Russian Language of the Russian Academy of Sciences, an optional acute accent ( ) may, and sometimes should, be used to mark stress. For example, it is used to distinguish between otherwise identical words, especially when context does not make it obvious: / (lock/castle), / (worthwhile/standing), / (this is odd/this is marvelous), / (attaboy/fine young man), / (I shall learn it/I recognize it), / (to be cutting/to have cut); to indicate the proper pronunciation of uncommon words, especially personal and family names (, , , , ), and to show which is the stressed word in a sentence ( ?/ ?/ ? Was it you who ate the cookie?/Did you eat the cookie?/Was it the cookie that you ate?). Stress marks are mandatory in lexical dictionaries and books for children or Russian learners.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What should be used to teach Russian learners according to the Russian Academy of Sciences?
Ah, so.. unanswerable

In the resulting Battle of Pusan Perimeter (AugustSeptember 1950), the U.S. Army withstood KPA attacks meant to capture the city at the Naktong Bulge, P'ohang-dong, and Taegu. The United States Air Force (USAF) interrupted KPA logistics with 40 daily ground support sorties that destroyed 32 bridges, halting most daytime road and rail traffic. KPA forces were forced to hide in tunnels by day and move only at night. To deny materiel to the KPA, the USAF destroyed logistics depots, petroleum refineries, and harbors, while the U.S. Navy air forces attacked transport hubs. Consequently, the over-extended KPA could not be supplied throughout the south. On 27 August, 67th Fighter Squadron aircraft mistakenly attacked facilities in Chinese territory and the Soviet Union called the UN Security Council's attention to China's complaint about the incident. The US proposed that a commission of India and Sweden determine what the US should pay in compensation but the Soviets vetoed the US proposal.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): Which army was trying to capture Teague and the Naktong Bulge?
Ah, so.. KPA

Persistent infections occur because the body is unable to clear the organism after the initial infection. Persistent infections are characterized by the continual presence of the infectious organism, often as latent infection with occasional recurrent relapses of active infection. There are some viruses that can maintain a persistent infection by infecting different cells of the body. Some viruses once acquired never leave the body. A typical example is the herpes virus, which tends to hide in nerves and become reactivated when specific circumstances arise.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): What never leave the body when acquired?
Ah, so..
Some viruses