If you have already obtained the 4th ICAO level and strive to get the 5th one, I would recommend you this textbook. It contains -a lot of idioms, phrasal verbs which can enrich your speech when you speculate on aviation-related topics. -grammar exercises View sample pages in the comments. DM for buying it -for Ukraine (PrivatBank) -for Russia (YooMoney) -for other countries (PayPal)