A:正方体
B:长方体
C:船形的
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.
评价实验方案
为证明细菌对植物遗体有分解作用,某小组的同学分别提出二种实验方案.二种实验方案的共同点:将同一种树的落叶分成甲、乙两组,实验过程中滴加蒸馏水使树叶保持湿润.
方案1:将甲组灭菌后放在无菌条件下,乙组放在自然条件下.
方案2:将甲、乙两组都进行灭菌处理,甲组放在无菌条件下,乙组接种细菌后放在无菌条件下.
分析:实验的设计要保证实验前对照组和实验组所处的____完全相同:而实验后,除单一变量外,____又处在相同的条件下.因此上述两个方案中,____的设计更科学合理.