What is biggest lake on the territory of russia

Baikal - is the  biggest lake on the territory of russia.  а вообще, если быть точным,  каспийское море - это самое большое озеро :

1) i'm a happy owner of my own house.2)i built it myself.

3)my house is a very big mansion.

4)it's a modern house.

They build  houses  every  year. they are building a house now. they will  built  this house next year. by the time  she  comes,  they have already  built  a house. when he arrived in  this city,  they … какая-то ошибка в варианте