| Most people today think of chocolate as
something sweet to eat or drink that can be easily found in stores around the
world. It might surprise you that chocolate was once highly treasured. Researchers at the University of Pennsylvania recently released a study. It suggested that people in Central and South America first gathered the cacao plant much earlier and for a different use than experts once thought. ① The researchers examined the chemistry of substances found in ancient clay containers that were over three thousand years old. They discovered that the substance came from an alcoholic drink made from the fruit of the cacao plant. The researchers believe it was the interest in cacao as an alcoholic drink that led to the use of its bitter seeds to make what is now known as chocolate. ② Historia A. Many people used cacao seeds in weddings to bless the couple with health. B. Aztec people used cacao seeds to pay taxes. C. Spanish people traded with Aztec to get cacao seeds. D. European people in ancient time liked bitter cacao drink. [单选题]工作场所的照明，应该保证足够的亮度。照明灯具的悬挂高度应不低于（）m，并不得任意挪动。
A.1 B.1.5 C.2 D.2.5 [单选题]目前，我国部分地区正在撤销街道办事处，街道办事处原有的社会管理、服务事务等职能已下放到社区居委会。只要是涉及老百姓利益的事情，社区都最大限度地遵照老百姓的选择，让老百姓参与进来自主决定。有专家表示，“这是城市管理中革命性的一种变革。”这种变革：( )
A.进一步巩固了我国基层的国家政权组织 B.充分发挥了居民委员会在社区管理中的作用 C.有利于让更多的政治组织参与到社区管理中来 D.从根本上改变了上层建筑，有利于促进经济社会的发展 [填空题]DNA的复制方式是（）。
[单选题]供气式呼吸防护用品，使用时应（ ），防止窒息。
A.先戴面罩后通气 B.先通气后戴面罩 C.直接戴上面罩 [多选题]电气设备上工作，检修设备和可能来电侧的断路器（开关）、隔离开关（刀闸）应断开（ ），隔离开关（刀闸）操作把手应锁住，确保不会误送电。
A.控制电源和保护出口压板 B.合闸电源和保护出口压板 C.控制电源 D.合闸能源 [单选题]按电流等级选择晶闸管的经验公式为IT( AV )≥()It(AV)。
A.0.5~0.8 B.1~2 C.1.5~2 D.2~3 [单选题]起升钢丝绳在放出最大工作长度后,卷筒上还必须留有安全圈且不得少于(
A.1圈 B.3圈 C.5圈 D.10圈 [单选题]激光全息检测利用的是光的( )现象。
A.反射 B.折射 C.衍射 D.干涉 [单选题]新中国成立后,我们觉在土地改革中对富农的政策是( )
A.彻底消灭富农 B.征收富农的土地财产归集体所有 C.保存富农经济 D.对富农进行社会主义改造 我来回答: 提交
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