1) Right answer:
que
El diario que yo leo es muy interesante
This lesson stands for relative pronouns. A relative pronoun is used to introduce a clause that describes a previously mentioned noun. One of the most important relative pronouns is que that means that, which, who, or whom and can refer to a person, place, or thing. Here que stands for el diario. This sentence translates into:
The diary that I read is very interesting
2) Right answer:
que
Hay mucha gente que no tiene casa en esta ciudad
Here we also use que. So here this relative pronoun stands for gente even though gente is still in the sentence. In this way, we can translate que here as who. So, in English this sentence means:
There are many people who don't have a house in this city
3) Right answer:
lo que
Yo no comprendo lo que tú dices
lo que means that which, what or the thing that and refers to an abstract idea. When we use this relative pronoun we are talking about a general idea. Thus, the translation of this sentence is:
I don't understand what you mean
4) Right answer:
que
El libro que nosotros usamos fue escrito por mi amigo
Here we also use que. So, this relative pronoun stands for el libro even though el libro is still in the sentence. Since libro (book) is a thing, then the relative pronoun translates into that. Therefore, in English this sentence means:
The book that we used was written by my friend
5) Right answer:
quien
Dime quien llegó
Quien is a relative pronoun that means who or whom and can only refer to a person. So here i want to know who arrived at a place. Thus, the translation of this sentence is:
who arrived?
So a response to this question might be:
María llegó in which case María replaces quien