50. The labels inside the clothes tell you          .

A. how to save money                B. whether they fit you or not

C. how to keep them looking best       D. where to get them dry-cleaned

51. From the passage we know that cheaper clothes          .

A. must be dry-cleaned         B. can not be washed

C. are always worse-made       D. can sometimes fit better

52. The best title for the passage should be          .

A. Buying Cheaper Clothes

B. Being a Clever Clothes Shopper

C. Taking Enough Money When Shopping

D. Reading the Labels Inside New Clothes

C

The Peppered Moth, a kind of insect (昆虫), is found in England. It is light brown in colour and likes to settle (定居)on trees which are also light brown. This makes the moth difficult to be found and birds are less likely to notice and eat it.

But with the development of industry (工业), smoke from factories began to reach the trees where the moth settled. It made the trees blacker. Then something very strange happened in industrial areas. The Peppered Moth began to change colour. It became darker as well. Though the change took several years. Some scientists soon noticed that newly-born moths were a little darker than usual.

A scientist called Kettlewell decided to make a careful study of this phenomenon (现象). He marked (作记号) some of the light moths and some of the darker ones, and set them free in the woods near Bermingham, an industrial city. Later, he recaptured (再捕获) as many marked moths as possible. The results were as follows:

Light moths Darker moths

Moths set free 201 601

Moths recaptured      34 (16%)      206 (34%)

Kettlewell’s research was done in the early 1950s. Soon Britain brought in new laws to reduce smoke and factory pollution.

Can you imagine what would happen to the Peppered Moth as the air became cleaner again?

53.  The Peppered Moth began to change its colour in industrial areas because         .

A. it itself liked to

B. it had to keep the environment

C. it was polluted by the smoke from factories

D. it could be like the colour of its living place

54.  From the results of Kettlewell’s research, we can see that         .

A. some light moths became darker ones

B. much more of the light moths were killed

C. more darker moths were killed in industrial areas

D. less than 1/5 of the light moths were being killed