单项选择题

Professor Laura believes that his research _________.

A．has been supported by many scientists
B．has a profound significance
C．has established a new theory on Vitamin Ｄ
D．has changed people's concept of skin cancer

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热门试题

单项选择题

It can be inferred from the passage that traditional skin cancer theory says _________.

A．natural sunlight may help prevent skin cancer
B．artificial light is too weak to cause skin cancer
C．exposure to the sunlight may cause skin cancer
D．Vitamin D is very important in preventing skin cancer

单项选择题

According to the passage, Professor Laura and Mr. Ashton's research on skin cancer _________.

A．is a big challenge to the traditional skin cancer theory
B．has been accepted by the medical world
C．is a new development to the old theory
D．is criticized by medical scientists