Complete the sentes .Use as or than.1 The Oka is shorter

Complete the sentes .Use as or than.
1 The Oka is shorter .....the Volga
2 Ben is ....strong as his brother
3 Andrew is not so tall....Jack
4 The weather in spring is more pleasent .... in late autumn
5 My bedroom is as comfortabl....my citting room .
6 My new book is more interesting....the old book .
7 The flowerbed are not so beautifol....the roses unnder the window .