题干

一个科研小组计划检测一种新研制的环保型除草剂是否能有效地除草,他们选用了三块相似的草地进行实验.第一块草地喷洒传统的除草剂,第二块草地喷洒与第一块等量的新型除草剂,第三块草地不喷洒任何除草剂.几天后,发现第一块草地的除草效果良好,而第二块草地与第三块草地长势相似,那么下列判断中合理的是(  )

A:实验失败

B:对照组设置不合理

C:新的除草剂能投入使用

D:新的除草剂可能没有除草效果

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答案(点此获取答案解析)

B

同类题3

先通读下面的短文,掌握其大意,然后在每小题所给的A、B、C、D四个选项中,选出可以填入空白处的最佳选项。

    I was always 1 and had too many things to do. Whenever my daughter caused me to change my plans, I thought to myself, “We don't have time 2 this.” So the two words I always said to her were: 3.

    The other day, the two of us rode to a 4 near our home. After shopping I bought her an ice cream, and she sat down 5 a table happily admiring the ice cream in her hand. Suddenly a 6 look appeared on her face. “Do I have to eat it up in a hurry, Mum?”

    I nearly cried when hearing this—the pains of a hurried life influenced(影响) my poor girl so deeply! As she looked at me waiting to know if she could 7 her time. I knew I had to make a 8. I thought of the times when I rushed (催促) my child through life, I began 9 what really matters in life….

    “You don't have to 10. Just enjoy it.” I said gently. Her whole face brightened and her shoulders 11. We sat side by side talking about things that interested us.

    When she got to the last bite (一口), she held it out to me, “ I 12 the last bite for you, Mum,” she said 13. As the icy taste put out my thirst, I realized I just got the present of a lifetime. I14 my child a little time… and in return, she gave me her last bite and reminded(提醒) me that things taste sweeter and love is easier to get when you stop rushing 15 life.