在“探究生长素类似物促进插条生根的最适浓度实验”中有关说法中错误的是（    ）

依据物质的分类标准可将一种物质归属多个类别。现有下列物质:

 ①      ②CH₂=CH₂ ③        ④CH₃CH₂CH₂CH₃

⑤                ⑥     ⑦CH₃CHO            ⑧

蚕的黄色茧（Y）对白色茧（y）、抑制黄色出现的基因（I）对黄色出现基因（i）为显性，两对等位基因独立遗传。现用杂合白茧（IiYy）相互交配，后代中白茧与黄茧的分离比为（   ）

以线段、、为三边的三角形是直角三角形的是（    ）

完型填空
     Monty was the son of a horse trainer. When he was in his ninth grade, he was asked to write a 1 about what he wanted to be and do when he grew up.
     That night he wrote a seven-page paper saying that someday he’d 2 a horse ranch (牧场). He wrote about his dream in great detail and he 3 drew a picture of a 200-acre ranch with all the buildings.
     He put a great deal of his 4 into the project and the next day he handed it in 5 his teacher. Two days later he received his paper back. On the front page was a large red F with a 6that read, “See me after class.”
     The boy with the dream went to see the teacher after class and asked, “7 did I receive an F?”
     The teacher said, “This is an 8 dream for a young boy like you. You come from a poor family. Owning a horse ranch requires a lot of 9. You have to buy the land. You have to pay for other things. There is no10you could ever do it.” Then the teacher added, “11 you rewrite this paper with a more realistic goal, I will reconsider your grade.”
     The boy went home and thought about 12 long and hard. He asked his father what he should do. His father said, “Look, son, you have to make up your own mind on this. However, I think it is a very important 13 for you.”
     Finally, after sitting with it for a week, the boy turned in the 14 paper, making no changes at all. He said to the teacher, “You can keep the F and I’ll keep my15.”