🤔 Do you understand? / ¿Lo entiendes?

懂 dǒng 
understand / entender

懂不懂?  Dǒng bù dǒng? 
Do you understand? / ¿Lo entiendes?

听懂了吗?  Tīng dǒngle ma?
Did you understand? (what you heard)
¿Has entendido? (lo que has oído)  

听不懂  Tīng bù dǒng 
Don't understand (what is heard) 
No entender (lo que se oye)

他的话我听懂了。Tā de huà wǒ tīng dǒng le.
I understood his words. / He entendido sus palabras.

看懂  kàn dǒng  
understand (what is seen, read, ...) / entender (lo que se ve, lee, ...)

看不懂   kàn bù dǒng 
don't understand (what is seen, ...) / no entender (lo que se ve, ...)

懂事   dǒngshì 
sensible, thoughtfulsensato, reflexivo

易懂   yì dǒng  
easy to understand / entendible 

难懂  nán dǒng  
difficult to understand difícil de entender

懵懵懂懂  měngměng dǒngdǒng  
muddled / confuso