题干

某学生测定的下列实验数据及取用药品的用量中,合理的有(   )

①未说明用量的实验,取用固体只盖满试管的底部,取用液体为2﹣3mL

②用10mL量筒量取了8.3mL水

③用托盘天平称取17.57g的石灰石

④给试管内固体加热时,试管应略向下倾斜

⑤向酒精灯内添加酒精至不要超过其容积的

2
3

⑥用滴管取1mL液体约20滴.

A:①②④

B:②③⑤

C:②⑤⑥

D:②④⑤⑥

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答案(点此获取答案解析)

C

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甲、乙、丙三辆小车同时、同地向同一方向运动,它们运动的图象如图所示,以下说法正确的是(   )

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如图所示,完全相同的两块长方形物块,在相同的水平地面上运动,拉力分别为F1和F2,且F1<F2.那么,所受摩擦力的大小关系为(   )

同类题3

阅读下面短文,从短文后各题所给的四个选项(A、B、C、D)中,选出可以填入空白处的最佳选项。

    A beggar was sleeping in the doorway of a fruit shop. The shop owner felt angry. He walked up to him and 1 him to go away in a rude manner, but the beggar did not seem to2 him and lay still there. The shop owner got much3, shouting that he was a beggar in disguise (假装) and4 cheated passers-by for money by making use of their kindness. At that time, it was the busiest moment of a day and the market was5with shoppers. They all blamed the beggar for6. Showing fear, the beggar7his face in an old blanket. What he received was bitter8rather than help.

    The next morning, it was drizzling. An old man, who went to the market early, found the beggar 9on the ground. He woke the beggar up and 10 asked whether he was cold or not, but the beggar made no 11. Then the old man12his hands gently, saying that they felt13. With these words, he ran home in a hurry, returned with a pile of14, picked out a sweater and urged the beggar to15 it on again and again. Seeing what happened, many other passers-by surrounded the beggar and gave him change one after another, showing16for him. It was not long before the beggar received a handful of 17.

    In many cases our behavior may have a great18 on the people around us because they are likely to19us. Therefore, we should pay special attention to what we do and say, trying to infect others with positive words instead of 20 ones.

同类题4


A note was on the blackboard ______ “All those who have a fever must leave school right now”.

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