1. a: hasn't come

b: went; hasn't returned

2. a: Have; already watched

b: watched

3. a: Did; talk

b: didn't see

4. visited

N°2.

1. I like learning something new. It makes me cleverer and I can lost my time very fast when I'm learning something.

2. I took part at very interesting talking English course. I enjoyed it!

3. расписал в пункте 2.

4. I took it up last year.

5. It lasted something like 3 months.

6. It was very useful for me. Now I speak English better because of this course.

7. I don't like sign language but maybe in future I will take it up.