The English adjective is a real candy with just one single form (in the positive degree) as compared to 24 gender-number-case forms in Ukrainian and Russian and 48 gender-number-case-declension forms in German. But the English verb… Everything about the English verb is very complicated. Well, the Ukrainian and Russian verbs are also complicated, but they are complicated in an absolutely different way, their synthetic morphology is tangled, all those numerous prefixes with unpredictable meaning, irregular forms that even native speakers have problems with (remember, our grammar is highly prescriptive), and many seemingly grammargrammatical categories which are realized not by inflection, but lexically, by derivation. Still, in the indicative mood active voice Russian has 3 tenses (present, past, and future), Ukrainian has 5 (present, past, pluperfect, and 2 future tenses with exactly the same meaning) or 4, pluperfect being practically not used nowadays. And English has 16… Simple, Continuous, Perfect, Perfect Continuous times Present, Past, Future, Future-in-the-Past is 16 tenses. Whyyy? Sooo? Manyyy? What's the purpose of that unbelievable number, if one can well live with 3 or even 2 tenses? How on earth there can there be 4 present tenses while I live pretty happily with just 1? Here again, in order to be able to use those 16 tenses one has to learn a new way of analyzing the reality, tracing the actions for continuousness and perfectness (needless to say that continuousness and perfectness are alien to Ukrainian and Russian ways of seeing the reality), and watching closely for a non-past tense not getting accidentally into a sentence with the past in the main clause. The Ukrainian and Russian tenses have relative meanings, and in the subordinate clauses of sentences like “He said he knew me” and “He said he would find me” Ukrainian and Russian use present and future verb forms respectively, so an English learner has to understand the idea of an absolute tenses which is extremely difficult, it's not because the very idea is complicated, but because that idea contradicts all of one's life experience, it's a fundamental difference which is usually learned by many, but understood and used in practice by few. And then, there's that weird question and negation do/does/did thing which is aggravated by the fact that some verbs need it and some don't… Slavic native speakers aren't even usually aware that there's such a thing as a negative form of the verb, you just put the particle ne before the verb, and that's all! (Czechs and Slovaks are, perhaps, aware, since ne is written together with the following verb in their languages). But in English, negating a verb is a complicated thing to do, it comes out that those “negator” don't / doesn't / didn't is inflected for tense, number, and person, very much like it's in Finnish, one would hardly expect such a situation from an Indo-European language. Because of that, the first English tense which is usually presented to a learner is Present Continuous (‘I am doing’), but here again, one faces all these I'm, you're, isn't, aren't, the words made of words of different parts of speech fused together into one, and you have to know when you can use them and when you're to use the full form. And also, there are phrasal verbs, like “go on” or “give up” with unpredictable meaning which compensate for the Slavic prefixed verbs. The English verbals have continuous and perfect forms (e. g. ‘to have been doing’, ‘having done’, etc.) which are not complicated to construct but very complicated to grasp the meaning of, and the way to use them correctly. Then go the modal verbs (“can”, “might”, “must”, and the like) which are not a simple thing in practically all the languages, but in English they are especially complicated, since one is supposed to distinguish the minute details and distinctions of, say, “can do”, “could do”, and “could have done”. I wrote “minute details”, since in Ukrainian and Russian the distinctions among the modal words are very rough. For example, we have the same word for “can” and “may” (U. могти, Ru. мочь) and Russian has the same word for “must”, “should”, “ought to”, “to have to”, “to be to”: должен (actually, there are different words for the latter must-like words, but they are rarely used).