单项选择题
A．They are caused by the magnetic pull from inside the sun. B．They are areas of high- level magnetism. C．They are actually black holes in the sun. D．They reach their peak in a cycle of 11 years.
28（）A．numberB．amountC．manyD．much
单项选择题28（）
A．number B．amount C．many D．much
Which of the following statements is supported by the p...
单项选择题Which of the following statements is supported by the passage（）
A．The sun shines constantly and gives out the same amount of energy every year. B．The cause of the sun' s fluctuations is its loss of energy with each passing year. C．It is sure that the energy sent out by the sun will drop when more sun spots appear. D．Fluctuations in weather patterns are the results of the pull of gravity.
Which of following is the best title for the passage（）A...
单项选择题Which of following is the best title for the passage（）
A．Fluctuations in Weather Patterns. B．Magnetism and the Sun Spots. C．The Size and Number about the Earth' s. D．Livingston' s New Theory about the Earth' s Climat
