活性污泥通常为（）（有时呈铁红色）絮绒状颗粒，也称为（）或“生物絮凝体”，活性污泥具有较大的比表面积，需要比较大的耗氧量。
参考答案：黄褐色；“菌胶团”
听诊犬胸部出现胸膜摩擦音常是于哪种疾病（）
A、胸膜炎
B、肺脓肿
C、大叶性肺炎
D、小叶性肺炎
选词填空（每词只能用一次）。
cold, cool, warm, surprised, relaxed
1. She is ______ she can play the guitar well.
2. The boy in sun-glasses (太阳镜) looks ______ very much.
3. It‘s very ______ in spring.
4. It is ______, please wear your scarf.
5. The boys are really ______ in the park.
