用所给词的适当形式填空 
1. A year ____(divide) into 12 star signs.
2. The first ____ (clone)sheep was named Dolly.
3. Stop____(argue) about it. Let’s be friends again.
4. The____(relax) music made us even____ (relax).
5. Amy has just had his bicycle____(repair).
6. It's a good ____ (choose) to____(choose) him as our monitor.
7. It's much____(sun) today than yesterday.
8. ____ (eat) too much is ____（health）for our health..
9. Your advice will be of great ____(valuable) to us .
10. I____ (colour) the card orange ____(cheer)you up and it brought you joy.

AB是圆O的直径，点C，D都在圆O上，连接CA，CB，DC，DB．已知∠D=30°，BC=3，则AC的长是____ ．

在生物分类等级中，生物之间的共同特征最多的和最少的分别是(    )