书城教材教辅科学读本(英文原版)(套装1-6册)
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第64章 第一册(64)

The stem of the plant makes its way up towards the light and air. Stems are not all alike. Trees and shrubs have hard, woody stems; herbs have soft green stems. Some stems are very slender and weak. There are twining stems, climbing stems, creeping stems, and underground stems.

Coal

"I have been thinking over our chat about things that burn," said Norah. "Why, Fred, we left out coal, and we all know coal is a good thing to burn. We use it to make our fires.""Yes, sister," said Fred. "We use coal for fuel, to make our fires. But teacher says there is so much to learn about coal, that we must take it by itself.

"Go and get a piece of coal, Willie. We will find out all we can about it.