With no explanation, label text_A→text_B with either "DON'T KNOW", "NO" or "YES".
text_A: Around this time Johann Bernoulli's two sons, Daniel and Nicolaus, were working at the Imperial Russian Academy of Sciences in Saint Petersburg. On 31 July 1726, Nicolaus died of appendicitis after spending less than a year in Russia. When Daniel assumed his brother's position in the mathematics/physics division, he recommended that the post in physiology that he had vacated be filled by his friend Euler. In November 1726 Euler eagerly accepted the offer, but his travel to Saint Petersburg was ultimately unsuccessful when that offer was revoked, and he instead fell back on his open invitation to be a professor of physics at the University of Basel.
text_B: Given the outcome of the hiring process, would Euler be lecturing to his students in Russian?
NO.