1.You are silly.You throw stones at dogs.(改写同义句） It's( ) ( )

1.You are silly.You throw stones at dogs.(改写同义句） It's( ) ( ) you to throw stones at dogs.
2.The new stadium is a huge one.(改写同义句）
The new stadium is ( ) ( ).
3.The captain was sure of saving his men.(改写同义句）
The captain was sure（ ） （ ）his men.
4.You can't live without air.(改写同义句）
You can't live if there is ( ) ( )