Sorry I don't speak russian, so I'm just gonna use english and chinese combined together to communicate with you. (1) 汉字很难记，即使我每天都复习，依然会忘记 first correction: 记得 to 记，记得means to remember，记means to memorize, under this context 记 is the correct choice second correction: 即使我每天都复习（汉字）, since you already mentioned 汉字 before, you don't need to say it again, we would understand you are talking about 汉字 If you mention it once again it just feels redundant. third correction: 也都忘记 to 依然会忘记 it is pretty common in chinese that if 即使 appears, there will be a 依然/仍然 following it. this is called 关联词. here 即使 + 依然 means although..... I still..... You used 都 in front of 忘记, it is not wrong but it is too strong, since 都 means all. it's kind of strong and unnatural when you say you forget all. 会 here has the same meaning as 'can' in english. I can still forget (汉字）, meaning that there is a certain probability that I will forget it. It will sound more natural. I don't have time now to give you more detailed suggestions, but if you like I can help you later. Good luck and keep up your chinese learning! 我现在没时间给你更多建议了，但是如果你愿意的话我可以之后继续帮助你。加油学习中文吧(^_^)

3）我有两个能力，既会挖，又不会挖。

2） 真奇怪，即使春天来了，天气也很冷。

可以交个朋友，我会汉语，先沟通有了语言环境才好学习，你教我英语或俄语，邮箱609324573@q q.com

第2和3句子没意思