"class" vs. "lesson"
The difference between "class" and "lesson" is not clear to me.
Whice one is more appropriate in these sentences?

1. I will have an English lesson/class tomorrow but I haven't finished the homework of last lesson/class yet.
2. We are going to have a Chinese class/lesson this Tuesday. I'd like to know what you want to talk about in our class/lesson.
3. I always choose the lesson/class of Mr. Li for every semester because I like his teaching style.

Question

"class" vs. "lesson"
The difference between "class" and "lesson" is not clear to me.
Whice one is more appropriate in these sentences?

1. I will have an English lesson/class tomorrow but I haven't finished the homework of last lesson/class yet.
2. We are going to have a Chinese class/lesson this Tuesday. I'd like to know what you want to talk about in our class/lesson.
3. I always choose the lesson/class of Mr. Li for every semester because I like his teaching style.

Answer

The word class generally means a gathering of people, who are students. There is an instructor/teacher. Often the class takes place in a classroom. The lesson is what is taught by the instructor/teacher.
Example sentences:
There are 30 students in the class.
The instructor greets the class before the lesson begins.
I thought that was a fabulous lesson; I like the instructor ‘s teaching style.
We have English class every morning at 8:00.
How many lessons has the instructor taught?

Answer

Thank you Phoebe! Thank you Steven! I didn't know before that "lesson" can indicate a one-on-one teaching.

Answer

A "class" is a place or event, and a "lesson" is what is taught there. 
A "class" implies a bunch of people whereas a "lesson" sounds more like one on one teaching.

1. "class, class"
2. "class, class" if more than one student will be there. If it is going to be one on one, "lesson, lesson."
3. class

Answer

"Lesson" is usually specific to what is being taught,  while "class" indicates the subject of learning.  For example, "Yesterday in English class we had a lesson on pronouns ".
 Here is another small difference;  if you were to say "I'm having an English lesson tomorrow" I would assume you mean one-on-on, like a private lesson, whereas a group studying a subject together at a school is a class.

#1 depends on if you mean small lesson or attending a class
2. First class, then lesson
3. Class