题目内容：

A purple tomato genetically engineered to contain nutrients more commonly seen in dark berries helped cancer in mice, British researchers said on Sunday. The finding, published in the journal Nature Biotechnology, bolsters the idea that plants can be genetically modified(changed) to make people healthier.

Cancer-prone mice fed the modified fruit lived significantly longer than animals fed a standard diet with and without regular tomatoes, Cathie Martin and colleagues at

the government-funded John Innes Center in Britain reported. “The effect was much bigger than we had expected.” said Martin, a plant biologist.

The study focused on anthocyanins，a type of antioxidant found in berries such as blackberries and blackcurrants that have been shown to lower risk of cancer, heart diseases and some neurological diseases. While an easy way to improve health, many people don’t eat enough of these fruits, the researchers said. Using genes from the snapdragon flower, the researchers discovered they could get the tomatoes to make anthocyanins---- turning the tomato purple in the process.

Mice genetically engineered to develop cancer lived an average of 182 days when they were fed the purple tomatoes, compared to 142 days for animals on the standard diet. “It is greatly encouraging to believe that by changing diet, or specific components in the diet. You can improve health in animals and possibly humans.” Martin said in a telephone interview.

The researchers warned that trials in humans are a long way off and the next step is to investigate( look into) how the antioxidants actually affect the tumors to promote better health. But the findings do support the formal research suggesting that people can significantly improve their health by making simple changes to the daily diet, other researchers said.

“It’s exciting to see new techniques that could potentially make healthy foods even better for us.” said Doctor Lara Bennett, science information office at Cancer Research UK. “ But it is too early to say whether anthocyanins obtained through diet could help to reduce the risk of cancer.”

1.The text mainly tells us _________.

A．what can prevent people from having cancer.

B．Scientists have developed cancer- fighting tomato.

C．ways to live much longer have been found by scientists.

D．genetically engineered food is good for people’s health.

2.In the first paragraph the underlined word “ bolster” probably means _______

A．change

B．reduce

C．support

D．test

3.Which of the following was NOT the result found in the study?

A．Blackberries and blackcurrants can lower risk of cancer.

B．The anthocyanins can make the purple tomatoes grow stronger.

C．Genes from snapdragon flowers can be put into common tomatoes.

D．Mice fed the modified fruit lived longer than the common ones.

4.According to Dr. Lara Bennett, the effects of anthocyanins through diet on human being________

A．are not certain now.

B．have been proved

C．are very harmful

D．are hard to be tested