我现在也摸出点规律来了。比如困难的“难”是用“又”代替了那个复杂的偏旁；邮局的“邮”是换了个简单点的声旁。有的保留了原字的轮廓，比如我爱你的“爱”；有的是取了原字的一部分，比如学习的“习”。对吧？
wǒ xiànzài yě mō chū diǎn guīlǜ lái le 。bǐrú kùnnan de “nán ”shì yòng “yòu ”dàitì le nà ge fùzá de piānpáng ；yóujú de “yóu ”shì huàn le ge jiǎndān diǎn de shēngpáng 。yǒude bǎoliú le yuánzì de lúnkuò ，bǐrú wǒ ài nǐ de “ài ”；yǒudeshì qǔ le yuánzì de yībùfèn ，bǐrú xuéxí de “xí ”。duìba ？
I'm able to make out some rules now. For instance, the word for ''difficult" uses the ''right hand radical" to stand for a more complicated radical. The word for ''mail" substituted a simpler phonetic element. Some kept the rough outlines of the original, such as the character for ''love." Some took a portion of the original character, like the word for ''practice." Right?