Read the passage and fill in the blanks with proper words.
Everyone knows that trees are very important to us. F( 1 )of all, trees do good to our health. They give out oxygen(氧气). We can’t live without trees. Secondly, trees can m( 2 )the world more beautiful. Trees are so important to us that we must p( 3 ) more trees. And we must d( 4 ) our best to look a( 5 ) them and we can’t destroy (破坏) them.