A:①③⑥
B:①②④⑤
C:①④⑤
D:③⑥
He is a much better (好得多) tennis player (运动员) than(比)me. When we play, he always wins(获胜)____________.
温室大棚栽培蔬菜时,夜间常常适当降低大棚内的温度,其最主要的目的是( )