题干

下列是“探究某种加酶洗衣粉使用的最适温度”的实验设计,最合理的是

A:加酶洗衣粉在30℃的水中洗涤效果没有37℃的好,说明37℃为最适温度

B:在不同温度的水中,加入相同的污物及不等量洗衣粉,看哪种效果好

C:取一系列不同温度、其他条件相同的水,加入等量相同的污物及等量加酶洗衣粉,看哪一个温度下洗衣粉的洗涤效果最好

D:将加酶洗衣粉与普通洗衣粉分别加入37℃的水中洗涤同样的污物,发现加酶洗衣粉效果好,说明加酶洗衣粉的最适温度为37℃

上一题 下一题 0.0难度 选择题 更新时间:2017-01-18 10:21:32

答案(点此获取答案解析)

C

同类题2

阅读下列短文,从每题所给的四个选项(A、B、C和D)中,选出最佳选项。

C

     Everyone has probably seen a movie or two about robots going against man. As a kid it was interesting, but not a reality. But today, when we look at how far scientists have come, it’s not just a funny thought but a real possibility.

     Honda has already created a robot with eyes, legs, arms and hands and it can act just like a person. There is no end to what a robot could do in the future. Just think what we can do in twenty to thirty years. We’re dealing with almost an entire new species (种类) of human-like robots that could be cleverer than us. Can we continue to use these robots in a way that they serve us, or will they become so wise that they will want independence (独立)?

     I am really not sure just how far scientists are going to perfect robots. But once this type of robot is made, they will be able to think, make decisions, sense the movement of others and decide what it wants to do.

     A new invention has led to the introduction of a female robot, which was introduced at an entertainment show in Vegas. The robot called Roxy sells for between seven and ten thousand dollars. It is built to accompany (陪伴) females. This female (女性的) robot companion is called true companion and you can find such robots on the Internet. Robots used to have limited uses, but now they are almost in every field. This has opened the door to many dangerous possibilities in the future.