1) I don't understand "span up this deal" 2) That makes sense, but I think "dissatisfied" is a better term than "unsatisfied" (https://www.dailywritingtips.com/dissatisfied-unsatisfied/) 3) That makes sense, but "came in handy" is a little colloquial, and "to us" is redundant 4) I apologize because I am not 100% sure with this, but I think the right sentence would be "My mother asked me to sweep the shelves before the guests came over". 5) "disbelief" not "disbelieve"; the former is a noun, the latter is a verb 6) You need a preposition "of" or "on" -- "I had only vague understanding of how the thing works". Also, Russian has no articles, so another way you could write it in English with an article is "I had only a vague understanding on how the thing works"