As an exchange student in Beijing, I’m currently preparing for HSK 4 of Chinese proficiency test. I was writing my practice exam when came across this question. What I want to say is LEARNING CHINESE is not HARD, but EXTREMELY HARD.
Like learning other languages, you need to practice making sentences and telling stories in the end. As it shows in the exam, HSK requires you to use certain word to complete sentences. One example it gives is 买卖（mai mai）which means “business”. “Even peddlers accept Alipay to do business”. Tricky thing is you may not even understand this example if you are not living in China. Cuz Alipay, or mobile payment is almost everywhere here.
I got stuck when I saw the word 黄牛，literally it meas cattle, but obviously not in this case. For me most difficult part in learning Chinese is understanding its culture.