气缸温度过高有何危害？
参考答案：
⑴使气体比容增大，影响打气量；
⑵在气缸内及气阀上形成各碳，加剧磨损；
用所给单词的适当形式填空。
1. Please bring some ______ (baseball) to school.
2. These are ______ (he) sister's books.
3. Where ______ (be) his notebook?
4. He needs two ______ (hat).
5. Can you ______ (take) the pencil to your teacher?
挤出的母乳在冰箱冷冻室可保存3个月左右。
