①frog{#blank#}1{#/blank#}                     A. It's small and yellow. 

②chick{#blank#}2{#/blank#}                           B. It's small and green.

③cow{#blank#}3{#/blank#}                            C. It's black and white.

  Air has no c{#blank#}1{#/blank#}, t{#blank#}2{#/blank#}, s{#blank#}3{#/blank#}or shape. We can't see it or smell it, but we can f{#blank#}4{#/blank#}it. Air is e{#blank#}5{#/blank#}around us. When air moves, it becomes w{#blank#}6{#/blank#}. The air moves quickly and the wind blows s{#blank#}7{#/blank#}. The air moves s{#blank#}8{#/blank#}and the wind blows g{#blank#}9{#/blank#}. Air is i{#blank#}10{#/blank#}to all of us. Without air, we will all d{#blank#}11{#/blank#}. Dirty air is b{#blank#}12{#/blank#}for our health. So let's try our best to k{#blank#}13{#/blank#}the air clean.