下面是青蛙的生殖和发育的几个时期，其正确的生殖和发育顺序是（ ）
①雄蛙鸣叫
②精子和卵细胞结合成受精卵
③排卵排精
④雌雄蛙抱对
⑤蝌蚪变态发育为青蛙
⑥受精卵孵化成蝌蚪
A：①②③④⑥⑤
B：①④③②⑥⑤
C：③②④①⑤⑥
D：②①③④⑥⑤
—______
They ________ carefully, but they didn't ________ anything.
— Chinese women's volleyball team won the gold medal in 2016 Rio Olympic Games.
—______ Chinese people were at that time!
