It seems that some young scientists ______.

单项选择题The author implies that the results of scientific research ______.

单项选择题The author asserts that scientists ______.

单项选择题The autor wants to prove with the example of Isaac Newton that ______.

单项选择题How could Dennis distinguish between a small ball and a large ball from a distance of 3 feet The large ball would produce ______.

单项选择题How could Dennis distinguish between a book and a pillow of the same size and at an equal distance in front of him A book would produce ______.