Kids shouldn't go out alone.
They must not go out by themselves

When I saw granny, she was alone.
When I saw granny, she was by herself

.

I went to the cinema alone.
I

.

My friend Fred lives alone.
He lives by himself

.

Tom and I built this house.
We ​

1 It usually  take me an hour to do my written exercises.
2 Where is Boris ?I Look for him.-He is having dinner.
3 I am looking a cassette recorder. Have you anything on sale?-Take a look at this little Sonic Walkman.-No,I don't want that kind.-Well,this Supersound might interest you.It is a good size?it is stereo and it has a radio to listen to the news.
4 I don't know about you,but I going out to the cinema.
5 Do you keep to any special diet?-Well,I don't  think it is good to eat a lot of meat.I usually have meat only once a week.I eat a lot of fruit and vegetables.
6 Не is learning  English now because he wants to get a better job.
Удачи=)

1) I go to the sea every summer (мы говорим, что каждое лето мы едем на море, т.е. это действие случается постоянно в одно и то же время, следовательно, мы ставим глагол в Present Simple)
2) She cleaned her room yesterday. (это действие произошло в а если точнее вчера. Здесь мы ставим глагол в Past Simple)
3) They are writing a test now. (Мы имеем в виду, что это действие происходит прямо сейчас, так что мы ставим глагол в Present Continuous) 
4) We will buy a new car next year. (Мы говорим, что действие произойдет в будущем, т.е. в следущем году, так что мы прибавляем к глаголу will)

Надеюсь, я тебе с: