题干

猪笼草是一种食虫植物,它以瓶状带盖的叶捕捉昆虫,并以其分泌物消化虫体.为检测此分泌物的性质,做了如下实验:取6支大小一样的洁净试管,加入经过不同温度处理的检测液后,再分别加入瘦肉块和马铃薯块,两小时后观察现象,记录如下表.请据表回答问题:

编号

加入物

条件

现象

1

2mL水+1cm3瘦肉块

室温

无明显变化

2

2mL新鲜分泌物+1cm3瘦肉块

室温

瘦肉块明显变化

3

2mL新鲜分泌物+1cm3瘦肉块

煮沸后冷却到室温

无明显变化

4

2mL水+1cm3马铃薯块

室温

无明显变化

5

2mL新鲜分泌物+1cm3马铃薯块

室温

无明显变化

6

2mL新鲜分泌物+1cm3马铃薯块

煮沸后冷却到室温

无明显变化

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    My father was always a good gardener. One of my earliest memories is standing without shoes in the freshly tilled soil, my hands blackened from digging in the ground.

    As a child, I loved following Dad around in the garden. I remember Dad pushing the tiller(耕作机) ahead in perfectly straight lines. Dad loved growing all sorts of things: yellow and green onions, watermelons almost as big as me, rows of yellow corn, and our favorite — red tomatoes.

    As I grew into a teenager, I didn't get so excited about gardening with Dad. Instead of magical land of possibility, it had turned into some kind of prison. As Dad grew older, his love for gardening never disappeared. After all the kids were grown and had started families of their own, Dad turned to gardening like never before. Even when he was diagnosed with cancer, he still took care of his garden.

    But then, the cancer, bit by bit, invaded his body. I had to do the things he used to do. What really convinced me that Dad was dying was the state of his garden that year. The rows and rows of multicolored vegetables were gone. Too tired to weed them, he simply let them be. He only planted tomatoes.

    For the first few years after he died, I couldn't even bear to look at anyone's garden without having strong memories pour over me like cold water from a bucket. Three years ago, I decided to plant my own garden and started out with just a few tomatoes. That morning, after breaking up a fair amount of soil, something caught the corner of my eye and I had to smile. It was my eight-year-old son Nathan, happily playing in the freshly tilled soil.