In French, we also often use the verb "to perfect" ("se parfaire") to mean "improve"; for instance, "I'm taking classes to perfect my English". I don't believe I've ever encountered that construction in English (if it is grammatically correct, then it is infinitely rarer)
It is, but in English "to perfect" has connotations of finality. I.e., "he perfected his technique" meaning it couldn't get any possibly better than it is. It's rare because perfection is rare.
"To improve" means that there is room for growth, which from what you say is implied by the French use of se parfaire.
In American universities, if you routinely got 12 out of 20 as your final mark you would be put on academic probation and risk not being admitted next term. Also, I don't know what classes you are taking, but acing mathematical or hard science classes in an American university is certainly no cakewalk.
It is, but in English "to perfect" has connotations of finality. I.e., "he perfected his technique" meaning it couldn't get any possibly better than it is. It's rare because perfection is rare.
"To improve" means that there is room for growth, which from what you say is implied by the French use of se parfaire.
In American universities, if you routinely got 12 out of 20 as your final mark you would be put on academic probation and risk not being admitted next term. Also, I don't know what classes you are taking, but acing mathematical or hard science classes in an American university is certainly no cakewalk.