题干

小刚通过显微镜观察洋葱表皮细胞,显微镜有5×和10×两种,物镜有10×和40×两种,下列组合中,观察细胞数目最少的是(   )

A:目镜5×,物镜10×

B:目镜10×,物镜10×

C:目镜5×,物镜40×

D:目镜10×,物镜40×

上一题 下一题 0.0难度 选择题 更新时间:2018-09-22 11:23:44

答案(点此获取答案解析)

D

同类题1

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。

    Annie, my neighbor's daughter, was away for her first term at college this year. She is a very sweet girl but just a bit shy. When her birthday month 1, I found out she was feeling a bit blue and 2.

    Her family is quite 3 and finances are tight, so there wouldn't be any birthday visitors.

    I wanted to send her a card and maybe a small gift to 4 her up. I got her school address from her mom and planned to 5 send her something. Then I got a(n) 6!  I thought perhaps I could give her a big 7. I bought some balloons, birthday hats and other small novelties (新奇玩意) at a one-dollar 8.  I took a small 9 and asked three other people in my area to sing Happy Birthday and send some birthday 10 to her. Other people found out 11 we were doing and added their voices, 12 it really sounded like we had a party 13 .

    Then I bought her a small present and a card as 14 originally. The real fun was 15 it to be sent. I arranged everything specially so it was like opening a birthday present!

    At the last minute, I added a pack of small cakes and a box of birthday 16 before sending it off. 

    I got a call a few days later. Annie said her roommate and one of her neighbors in her school got together with her and held the party for her once it arrived. She sounded so 17 and I was so glad that she had some friends to 18 her special day with her.

    It was such an easy and fun thing to do. The people who helped me make the tape still laughed and talked about the 19 experience. And Annie told me it was the most fun birthday she can 20!