How to translate these sentences into Korean by using causative verbs ('사동사')? I am struggling with the Korean causative verbs these days but it is difficult a little. As far as I'm aware, the causative verbs are made by adding 이, 히, 리, 기, 우, 추 (the suffixes) to the stem of some verbs. For example, 먹이다 ( <- 먹다), 읽히다 (<- 읽다), 웃기다 (<-웃다), etc. I later figure out that among these most common causative verbs which are listed in my Korean Grammar Book, there are no verbs in '하다' form. 

In that case, am I right if I understand that I can't add 이/히/기/리/우/추 to any verbs in '하다' form to make a 사동사?

In that case, how could I translate this sentence into Korean?
The sentence is as follows: 'Her mother made her wash her face by herself'?
(As she's just a child, she couldn't wash her face and her mother step by step taught her).
It's a little easier for me to translate the sentence 'Her mother made her wear something (using 입히다), read something (using 읽히다), etc. But how about 세수하다?

With 세수하다, I came to the idea that I could add 게 하다 to make it become a 사동사. But as a foreigner learning Korean, I think there is a subtle difference for the meaning if I add 이/히/기/리/우/추 and 게 하다. I understand that if I add 게 하다, I use my words (by speaking out) or use another indirect methods to make someone do something while the use of verbs adding the suffixes is wider. But, if I want to add 이/히/기/리/우/추, is that possible?