题干

猪笼草是一种食虫植物,为了验证猪笼草分泌液中有蛋白酶,某学生设计了两组实验,如下图所示。在35℃水浴中保温一段时间后,甲、乙试管中加入适量的双缩脲试剂,丙、丁试管中不加任何试剂,下列实验能达到目的的是

A:只有实验①能

B:只有实验②能

C:实验①、实验②都能

D:实验①、实验②都不能

上一题 下一题 0.0难度 选择题 更新时间:2015-06-25 05:36:04

答案(点此获取答案解析)

B

同类题3

根据短文内容,从短文后的选项中选出能填入空白处的最佳选项。选项中有两项为多余选项。

Fitting in fitness

    Do you find excuses not to exercise? ____ Here are a few ways to get you going.

Do what you love.

    The easiest way to fall into the habit of doing exercise is to choose an activity you enjoy — one that doesn't feel like exercise, even though it is. ____ If you play to your strengths, you'll find fitness activities you can enjoy for years.

Choose your hour.

    Studies have shown that people who work out in the morning are most likely to stick with a routine. By doing exercise before the day starts, they can avoid the last-minute scheduling conflicts. But if you' re not a morning person, choose whatever time works best for you. ____

Call it by another name.

    ____ If it's something you have to do anyway — like washing the car or planting some bushes in the yard — you'll achieve two goals at once.

Partner up.

    Exercise is more fun when you do it with others. ____ On days when your motivation is low, you' re more likely to stick with the programme to avoid disappointing your exercise partners. You can also train with an expert. A personal trainer will help you set goals, design a personalized fitness programme, and vary your routine to keep it challenging.

A. Ask yourself: what am I good at?

B. Make fitness part of your social routine.

C. For example, you can join a running, walking, hiking, biking or tennis club.

D. If you're in top form from noon to 1 pm, aim for a lunchtime workout.

E. Would you rather do anything else — even sort your socks or clean the fridge?

F. If a damp T-shirt is not your idea of a good time, try gentler forms of exercise.

G. Substitute some challenging household activity for the standard exercise routine.