题目内容：

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Popeye the Sailor Man(《大力水手》)first became a popular cartoon in the 1930s. The sailor in that cartoon ate lots of spinach(菠菜)to make himself strong. People watched him,and they began to buy and eat a lot more spinach. This cartoon helped sell 33% more spinach!Spinach became a necessary part of many people's diets. Even some children who hated the taste began to eat the vegetable.

Many people thought that the iron(铁)in spinach made the sailor strong,but it is not true. Spinach does not have any more iron than other green vegetables.

Earlier,the people who studied the food made a mistake. In the 1890s,a group of people studied what was inside vegetables. This group said that spinach had ten times more iron than other kinds of vegetables. The group made a mistake,but everyone accepted it.

Today,we know that spinach can't make a person very strong. However,spinach does have something else that the body needs—a vitamin called folic acid(叶酸)．

It is interesting to point out that folic acid can help a person stay healthy. Maybe it was really the folic acid that made the sailor strong.

1.Popeye the Sailor Man is a popular ________.

A.comedy B.thriller

C.Beijing Opera D.cartoon

2.What's the main idea of the first paragraph?

A.Popeye the Sailor Man was a popular cartoon in the 1930s.

B.Many people wanted to be strong.

C.The cartoon Popeye the Sailor Man made spinach popular.

D.Spinach was popular in the 1930s.

3.The research group which told people that spinach ________ made a mistake.

A.had less iron than other vegetables B.had more iron than other vegetables

C.made the sailor strong D.had more folic acid than other vegetables

4.According to the passage，maybe ________ made the sailor strong.

A.the iron B.the folic acid

C.the coffee D.the sugar