蚕丝是高级的纺织原料，被称为“纤维皇后”“第二肌肤”的美称。（   ）

某同学为自己设计了一盏调光灯，其原理如下图所示，已知灯L的规格为”6V3W”（不考虑灯丝电阻的变化），滑动变阻器R的阻值范围为0~12Ω，电源电压恒为6V。

阅读短文，完成句子。
    Lychees grow in the south (南方) of China. They are small with red peel (果皮). Most people like to eat them, because they are sweet and full (充满的) of juice.  There is an old story about lychees. Yang Yuhuan loved lychees very much. Lychees have a lot of vitamin C. It is very important for people. Vitamin C can make children more healthy. So many parents often buy lychees for their children. Amy and her mum are in the fruit shop now. What fruit are they going to buy? Look! They are buying lychees
从文章中找到适当的单词或短语填空，完成句子。

关于速度和加速度，以下说法中正确的是(    )

下列属于禁止吸烟标识的是（    ）