Translated one sentence from Russian to English...

and added documentation for {parent}

docs/en/tags/extends.md

@@ -19,7 +19,7 @@ Also if a child template extends a parent template with the `{extends}` tag it m
 
 ### {use}
 
-Что бы импортировать блоки из другого шаблона используйте тег {use}:
+Import the blocks defined in another file. Specifying blocks in this template will override those from the other file.
 
 ```smarty
 {use 'blocks.tpl'} merge blocks from blocks.tpl template
@@ -31,6 +31,8 @@ Also if a child template extends a parent template with the `{extends}` tag it m
 
 ### {parent}
 
+Uses the code from the block as defined in the parent.
+
 ```smarty
 {extends 'parent.tpl'}
 
@@ -43,7 +45,7 @@ Also if a child template extends a parent template with the `{extends}` tag it m
 
 ### {paste}
 
-Paste code of any block
+Pastes the code of any block
 
 ```smarty
 {block 'b1'}