I just wanted to point out one mistake in lesson my nationality, my address, my job..
in the test there is question;

4. How to answer "yes, we have" to the question "Kudamono ga arimasen ka?" (don't you have any fruits?) ?

a. Hai, arimasen (はい、ありません)
CORRECT ANSWER: Iie, arimasu (いいえ、あります

This is wrong, it should be ;
1. Hai, arimasu
2. Iie, arimasen

arimasen is negative form and can be used only with iie, and the opposide arimasu means have, so yeah, I have is hai, arimasu...

That`s it!
Good job otherwise^^!

No no no
In japanese when you have a question with a negative form, if you answer "hai" it means like "in fact we don't have any fruits".
If you use "hai" you confirm the negative question
On the contrary,if you use "iie" ,you refute the negative question.

Kudamono ga arimasen ka? Don't you have any fruits ?

hai,arimasen. no we don't (literally "yes,we don't")
iie arimasu yes,we have (literally "no (don't worry) we have fruits")

Ah! There is a pause!

Element is right, it was the tricky part of the lesson and a hard point to understand for foreigners. It's easier to understand when you translate はい into "Yes, it's correct" and いいえ into "No, it's wrong".