单项选择题According to the text, recycling
单项选择题Which of the following is TRUE according to the passage
单项选择题The author uses figures in Paragraph 2 to show
单项选择题What affects the amount of carbon-14 on earth().
A. The lifecycle of trees. B. The number of trees. C. The intensity of solar burning. D. The quality of air.
单项选择题2().
A.selling B.sales C.sale D.sold