安全色是传递安全信息含义的颜色,机器转动部件的裸露部分,如飞轮、齿轮、皮带轮等轮辐部 发布时间:2018-05-09 12:48 │ 来源:www.tikuol.com 题型:单项选择题 问题: 安全色是传递安全信息含义的颜色,机器转动部件的裸露部分,如飞轮、齿轮、皮带轮等轮辐部分一般使用()进行标识。A.红色B.黄色C.蓝色D.绿色
题型:单项选择题 某物理兴趣小组为了探究地球表面水吸收太阳能的本领,做了如下实验:用一脸盆装6kg的水,水的表面积为0.1m2,经过太阳光垂直照射15min,水温升高了5℃.问:(1)实验时6kg的水15min内吸收了多少热量? (2)平均每分钟1m2水面吸收的热量是多少?(3)若用加热的方式使同质量的水升高相同的温度,至少需要燃烧多少m3的液化气?(假设液化气燃烧放出的热量的40%损失,液化气的热值是5.0×107J/ m3) 查看答案
题型:单项选择题 用方框中所给单词的适当形式填空,使句子通顺、正确。每个单词限用一次。nature, influence, free, against, please 1. The themes of the story are about the social rules and ________. 2. His parents were very _______ with him when he passed the final exam. 3. We are still _______ by Confucious' thoughts. 4. Which team will you play ________? No. 2 Middle School. 5. The Great Barrier Reef is one of the most famous _______ wonders in the world. 查看答案