A-A+
By if the fuel isn't there the spark is usel
问题详情
By "if the fuel isn"t there, the spark is useless", the author means______.
A．carbohydrates, protein and fat are enough to sustain a human life
B．vitamins and minerals are virtually of no value
C．carbohydrates, protein and fat are as important as vitamins and minerals
D．without carbohydrates, protein and fat, vitamins and minerals are of no use请帮忙给出正确答案和分析，谢谢！
参考答案
正确答案：D
解析：本题的关键是理解最后一段的真正意思。A和B项内容错误，C项不符合原文中的in very different proportions(比例不同)。D项的意思为：没有碳水化合物、蛋白质和脂肪(the wood in the fireplace／fuel)，维生素和矿物质(the match／spark)不起作用。
