葳蕤9999
Turn off the lights before you leave the classroom.离开教室前关灯。Lock the doors and windows before you leave the classroom.离开教室前锁好门窗。Don't run too fast through the desks and chairs.不要在桌椅旁追跑打斗。Don't climb up or make your body outside the windows.不要爬窗户或将身体探出窗外。Don't touch the switches in the classroom when your hands are wet.湿手不要触摸教室里的开关。
小肚巨肥
答案：protect；safe．分析句子，句中的to是不定式符号，用不定式作为后置定语修饰前面的ways，保护用动词protect，故protect；保证安全结合系动词keep保持，后加形容词构成系表结构，用形容词safe表示安全的，故答案是protect；safe．
小树旁的小树
keep classroom safekeep the safety of classroommantain the safety of classroommantain classroom saferetain the safety of classroom
