题目内容：

Dandelions（蒲公英） are common weeds that grow in many places around the world. In different _______, dandelions take different shapes. Scientists have long _______ that different habitats led to the creation of _______ species, and that differences in form are actual proof of different species. _______, according to Turesson, it is also possible that a _______ species takes different shapes dependent on the habitats it _______ in. To study this, I have looked at two dandelions growing in different habitats. The one, ________ I will call Dandelion 1, grows in a grass field that lies in the _______. The other Dandelion, Dandelion 2, grows in the shadow, eg _______ the trees or behind a shed. The grass field is hot and _______. The shadow is cool and wet. So, what are the _______ between Dandelion 1 and 2?

Dandelion 1 is dark green, and its ________ are short and quite thick. Most of the leaves lie _______ on the surrounding grass. The flowers are short. Dandelion 2, on the other hand, looks very differently. The leaves are long and ________green, Most leaves stand in a vertical position. The flowers also _______ tall.

Dandelion 2 _______ strong and tall. It is clear that it grows very well in the ______, and that has enough ________ and space to grow into a big plant. Dandelion 1, on the other hand, is small and dark. It seems that the ________ in the grassland make it difficult for this dandelion to grow into a big plant.

________, the conditions in the two different habitats result in different shapes for these dandelions. For Dandelion 1, the sun makes the grass field hot and dry. In order to save water, it grows short and thick leaves.

1.A. houses    B. habitats    C. parks    D. countries

2.A. disagreed    B. provided    C. believed    D. calculated

3.A. new    B. good    C. old    D. bad

4.A. However    B. Therefore    C. Thus    D. Otherwise

5.A. same    B. different    C. strange    D. single

6.A. plants    B. works    C. takes    D. grows

7.A. what    B. which    C. that    D. when

8.A. world    B. mountain    C. sun    D. valley

9.A. under    B. over    C. upon    D. between

10.A. Humid    B. Wet    C. Soft    D. dry

11.A. similarities    B. advantages    C. differences    D. disadvantages

12.A. seeds    B. leaves    C. weeds    D. woods

13.A. flat    B. apart    C. dead    D. logical

14.A. dark    B. bright    C. artificial    D. familiar

15.A. lie    B. break    C. stand    D. perform

16.A. sounds    B. smells    C. feels    D. looks

17.A. swallow    B. shallow    C. shadow    D. shape

18.A. sunshine    B. leaves    C. honey    D. water

19.A. Conditions    B. Occasions    C. Situations    D. preparations

20.A. Fortunately    B. Obviously    C. Consequently    D. Accidentally