题目

It was Sunday yesterday.Bruce went to play football with his friends.Soon he felt hot and took off his coat. On his way home, he forgot  to put it on again. This morning he felt unwell and couldn't go to  school. His mother told him to stay in bed and then went to buy some medicine for him. An hour later he wouldn't lie there, so he stood by the window. The sun was shining and the birds were singing in the trees.Soon his mother came  back and said, It's warmer outside. Go to sun yourself after you take the medicine.     Bruce went out and sat on a step and played alone. At that 下列关于生活材料的说法中，正确的是（　　）A．三大合成材料是指塑料、合成纤维和复合材料B．热塑性塑料与热固性塑料均具有线型结构，加热到一定温度都能软化、熔化C．复合材料一般是以一种材料作为基体，另一种材料作为增强剂D．钢化玻璃与普通玻璃的主要成分不同