问题 解答题

人图表示将叶片制成切片,并在显微镜下观察到叶片结构的情况.据图回答问题:

(大)①是叶片中的______,具有输导水、无机盐和有机物的功能.

(地)②是______,其细胞里含有较少的叶绿体.

(3)③______是叶片与外界进行气体交换的门户,它的开闭由两个肾形的______控制.

(4)成熟的植物细胞具有④______.

答案

(1)在叶片中具有输导作用的是导管和筛管,导管把水分和无机盐从根运向茎和叶,筛管把叶制造的有机物运到茎和根等部位,它们都位于①叶脉中.

(2)不论栅栏组织还是②海绵组织,它们都属于叶肉,在细胞中含有叶绿体,是光合作用的主要场所.但是②海绵组织细胞里含有较少的叶绿体.

(3)叶片能与外界进行气体交换的结构是表皮内的③气孔,它是由半月形的保卫细胞围成,保卫细胞的吸水和失水控制着气孔的开和闭.

(小)幼小的植物细胞,具有许多小而分散的液泡,在电子显微镜下才能看到.以后随着细胞的生长,液泡也长了,互相并合,最后在细胞中央形成一5了的中央液泡.具有一5了的中央液泡是成熟的植物生活细胞的显著特征

故答案为:(1)叶脉

(2)海绵层

(3)气孔,保卫细胞

(小)中央了液泡

填空题
阅读理解

         After finishing my shopping, I headed for the checkout

counter but was blocked in the narrow passage by a young

man that appeared to be about sixteen years old. I wasn’t in a

hurry, so I patiently waited for the boy to realize that I was

there.

After a little while, he waved his hands excitedly, in the air and shouted in a loud voice, "Mommy, I'm here.Mommy, I'm here." It was obvious now, he was mentally challenged.Suddenly, he turned and saw me standing so close to him.His eyes widened and watched me surprisingly.He turned and saw me standing so close to him. His eyes widened and watched me surprisingly. I stepped back and asked, " Hey, buddy, what’s your name? " " My name is Denny and I'm shopping with my mother," he responded proudly."Wow," I said, "that's a cool name.I wish my name was Denny, but my name is Hal." "Hal like Halloween?" he asked."Yes," I answered."How old are you, Denny?" "How old am I now.Mommy?" he asked his mother as she came over from the next passage."You' re fifteen years old, Denny; now be a good boy and let the lady pass by." I continued to talk to Denny for several more minutes about summer vacation, bicycles and school.I watched his brown eyes dance with excitement.

As we were talking, he suddenly ran toward the toy section.

Denny's mom thanked me for taking the time to talk with her son.She told me that most people wouldn' t even look at him, much less talk to him…I told her that it was my pleasure and then I said, " Denny is a blue rose and if I didn' t stop and smell that rose with my heart, I would miss a blessing from God."

She looked more puzzled.I told her that there are plenty of red, yellow and pink roses in God's garden, however, blue roses are very rare and should be appreciated for their beauty and distinctiveness (特殊之处).Denny is such a "blue rose" in God's garden.     

46.The story may happen      .

A.in a school         B.during the summer vacation

C.in a super market     D.in the toy section

47.The boy's brown eyes dance with excitement because       .

A.he was the center of someone's attention  

B.Denny is a cool name

C.he is shopping with his mother           

D.he likes summer vacation

48.We can infer from the passage that Danny ______.

A.was mentally challenged       B.is 15 years old 

C.was often very lonely and neglected        D.is a ‘blue rose1’ in God's garden

49.From the passage we can learn that _______.

A.there are plenty of red, yellow and pink roses in God’s garden     

B.blue roses'are very rare and should be appreciated                                    

C.most people wouldn’t even look at Denny

D.every person should be appreciated in our life