I am Chinese, I started to learn Russian 7 years ago, in my University time.I am still learning Russian now. If I have to be honest, everything in Russian is so difficult. For example:
我是中国人，7年前在大学里开始学俄语，现在仍然在学。说实话，俄语里所有内容都很难。比如：
Род (gender), There are 3 genders for every noun. Masculine, feminine and neuter nouns. Once you use a different gender, you might have to change all the sentence.
Род（词性）：每个名词有三种词性，包括阳性、阴性和中性名词。一旦改变了一个词的词性，可能整句话都得改。
Падеж (declension), there are 12 different declensions for every single word. Singular numbers 1st to 6th, plural numbers 1st to 6th.
Падеж（词尾变化）：每个单独的词都有12种不同的词尾变化，第一到第六有单数形式，还有复数形式。
Склонение (Conjugation), that is hell for foreigners. You can find more than 100 different forms from a single verb. There are special forms for present tense, past tense, future tense. I want ,you want, she/he/it wants they want, we want are all different. Let me show something to you:любить (love)
Склонение（动词词性变化）对外国人来说简直是噩梦。一个动词可以有100多种不同形式。现在时、过去时和将来时都有特殊形式。“我想”“你想”“她/他/它想”“他们想”“我们想”形式都不一样。给你看点东西：любить（爱）

These are not all, there are plenty of exceptions in Russian language. You should try very hard to remember every single rule. But finally you will find exceptions in grammar are everywhere…
这还不是所有的，俄语中还有很多特例。你需要非常努力地记住每一条规则，但最终你会发现语法中的特例无处不在……
I often doubt about this. If I chose to learn French or some other simple languages. How well I can speak?But right now I still can’t speak Russian as well as I can in English. I only leant English hard in my school time. Since I started to learn Russian I almost gave up my English. (in fact, I did not learn it very hard, average 4–6 hours per week) .
我经常怀疑，如果当初选择学法语或其他简单的语言，我现在说得会有多好？但现在我的俄语仍然没有英语说得好，我只在上学期间努力学英语，自从开始学俄语英语几乎就放弃了（其实我也没有特别努力，平均每周4-6小时）。
Now I am living in Russia and still learning Russian language.
现在我在俄罗斯生活，仍然在学俄语。