【英语时差8,16】枫糖浆到底是什么？（上）

（单词翻译）

If you take a spring walk through the woods in many parts of the Northeast, you’ll find buckets hanging from the sides of maple¹ trees. Drop by drop, the buckets are filling up with the slightly sweet sap from the trees. When that sweet liquid is boiled down, it becomes maple syrup², all ready for a plate of pancakes. Colonists³ arriving from Europe learned from the American Indians how to tap maple trees and boil the sap into syrup. For a long time, maple syrup was the only concentrated sweetener available on this continent. Today, little is known for certain about why a sugar maple produces such sweet sap. The sugar in the sap is made in the leaves by photosynthesis⁴ — the same process that all green plants use to convert⁵ water, sunlight, and carbon dioxide into food. So the best year for maple syrup is one with the best conditions for photosynthesis — a sunny summer and fall with a late frost. A cold winter and a heavy snow fall to keep the roots cool in the spring also improve the syrup harvest.