题干

下列实验步骤错误的是( )

A:观察植物细胞的有丝分裂:解离→染色→漂洗→制片→观察

B:检测脂肪:切取花生子叶薄片→染色→洗去浮色→制片→观察

C:观察质壁分离:撕取紫色洋葱鳞片叶表皮→制片→观察→滴加蔗糖溶液→观察

D:观察叶绿体:取黑藻小叶→制片→观察

上一题 下一题 0.0难度 选择题 更新时间:2018-12-04 11:22:23

答案(点此获取答案解析)

A

同类题2

完形填空(共20小题;每小题1.5分,满分30分)

阅读下面的短文,从短文后各题所给的A、B、C和D四个选项中,选出可以填入空白处的最佳选项,并在答题卡上将该项涂黑。

    While high school does not generally encourage students to explore new aspects of life,college sets the stage for that exploration. I myself went through this 1 process and found something that has changed my 2 at college for the better:I discovered ASL-American Sign Language(美式手语).

    I never felt an urge to 3 any sign language before.My entire family is hearing,and so are all my friends.The 4 language were enough in all my interactions(交往).Little did I know that I would discover my 5for ASL.

    The 6 began during my first week at college. I watched as the ASL Club 7 their translation of a song. Both the hand movements and the very 8 of communicating without speaking 9me. What I saw was completely unlike anything I had experienced in the 10 .This newness just left me 11 more.

    After that, feeling the need to 12further, I decided to drop in on one of ASL club`s meetings. I only learned how to13 the alphabet that day. Yet instead of being discouraged by my 14progress,I was excited. I then made it a point to 15those meetings and learn all I could.

    The following term, I  16an ASL class. The professor was deaf and any talking was  17 . I soon realized that the silence was not unpleasant. 18 , if there had been any talking, it would have 19us to learn less. Now, I appreciate the silence and the 20way of communication it opens.