题目内容：

.Can you imagine your doctor warning that taking a bath could be unhealthy? In the early 1800s, many doctors thought that bathtubs(浴缸) could carry diseases, so they advised against their use. The advice wasn’t based on personal experience, because few of the doctors owned bathtubs. The White House did not even have a bathtub until 1851.

In the 19th century, only one home out of six had a bathroom. A child took only one bath a week. On Saturday nights, children all lined up for their turns to wash in a wooden bathtub in the kitchen. Mothers had to boil the water on the stove and carry it over to fill the bathtub. It’s no wonder that children could not jump into a bathtub as they do today.

When the first bathtubs were introduced, even their makers weren’t sure whether the new fashion would last. They advertised their products as water containers that “could be used as bathing tubs”.

The bathtub became popular in America shortly after World War I. By then most middle-class families had indoor taps. At first most bathtubs were made of wood, but as the popularity of the product increased, so did the creativity of bathtub makers. Before porcelain(瓷) bathtubs there were rubber ones like the plastic swimming pools kids use today. In the past few years owners often invited guests to see them. They told their friends how wonderful baths in these bathtubs could be.

Now doctors no longer warn that bathtubs carry diseases. Instead, they tell their patients about the benefits of frequent bathing in the bathtubs. Maybe one of the best reasons why doctors encourage frequent trips to the bathtub is that bathed patients smell better!

47. Many doctors in the past were against using bathtubs because ______.

A. they didn’t have their own bathtubs

B. they thought bathtubs could carry diseases.

C. the children might hurt themselves in the bathtubs

D. bathtubs were too expensive for the common families

48. Why couldn’t children jump into a tub in the 19th century as they do today?

A. It was unhealthy to do so.      B. The bathtubs were not enough.

C. Mothers were always busy.     D. The bathtubs were made of wood.

49. Which of the following is true according to the text?

A. Some different materials can be used to make bathtubs.

B. In the 19th century only one home out of seven had a bathroom.

C. The bathtub became popular when they were introduced to the market.

D. Children prefer the bathtubs made of plastic to those made of porcelain.

50. It can be inferred from the last paragraph that ______.

A. all the doctors have bathtubs in their homes

B. the doctors have realized the advantages of bathtubs

C. the doctors will make lots of money by advertising bathtubs

D. the patients should take a bath before going to see a doctor