皮皮学,免费搜题
登录
搜题
【单选题】
听力原文: It was an Italian inventor who created the first wireless device for sending out radio signals in 1895. But not until the American inventor Lee De Forest built the first amplifying vacuum tube in 1906 did we get the first radio as we know it. And the first actual radio broadcast was made on Christmas Eve of 1906. That's when someone working from an experimental station in Brand Rock, Massachusetts, arranged the program of two short musical selections, a poem and a brief holiday greeting. The broadcast was heard by wireless operators on ships with a radio through several hundred miles. The following year, De Forest began regular radio broadcasts in New York. These programs were similar to much of what we hear on the radio today in that De Forest played only music. But because there were still no home radio receivers, De Forest's audience consisted of only wireless operators on ships in New York harbor. There is no doubt that radio broadcasting was quite a novelty in those days. But it took a while to catch on commercially. Why? For the simple fact that only a few people, in fact, only those who tinkered with wireless telegraphs as a hobby, owned receivers. It wasn't until the 1920's that someone envisioned mass appeal for radio. This was radio pioneer, David Sarnoff, who predicted that one day there would be a radio receiver in every home. When was the first actual radio broadcast made?
A.
On Christmas Eve of 1906.
B.
On Christmas Eve of 1960.
C.
On Christmas Eve of 1895.
D.
On Christmas Eve of 1859.
拍照语音搜题,微信中搜索"皮皮学"使用
参考答案:
参考解析:
知识点:
.
..
皮皮学刷刷变学霸
举一反三
【多选题】以下哪些属于特殊类型的痤疮
A.
聚合性痤疮
B.
药物性痤疮
C.
寻常痤疮
D.
婴儿痤疮
E.
月经前痤疮
【多选题】以下哪些属于新型铂类药物的研究发展方向?( )
A.
四价铂前体药物
B.
大体积稳定配体的二价铂衍生物
C.
具有功能离去基团的铂类药物
D.
铂类药物纳米制剂
【多选题】以下哪些措施属于避免除草剂产生药害的措施( )?
A.
在大面积使用某种除草剂前一定要先试验
B.
在异常气候下不要使用除草剂
C.
邻近有敏感的作物,不要使用易挥发或活性高的除草剂,以免产生飘逸药害
D.
合理混用除草剂是防止药害的有效方法,另外对那些不太安全的除草剂应加上安全剂后再使用
【简答题】请同学们 课查阅资料,完成以下问题: 1. 目前社会 中有机磷中毒的现象是否多见 ? 2. 引起 有机磷中毒的原因有哪些 ? 3. 哪些 药物属于有机磷农药?
【简答题】—Imagine you are outside when earthquake comes. What should you do? ­ — Go to open space away from buildings or tree. A.the; the B.the; an C.an; the D.an; an
【单选题】青霉素皮内试验结果,哪项为阳性反应:( )
A.
皮丘无改变
B.
全身无自觉症状
C.
皮丘周围无红肿
D.
D .皮丘直径大于1cm
E.
无伪足.痒感
【多选题】以下哪些属于心肺耐力测试前的准备工作?( )
A.
采集病史、体格检查
B.
签署知情同意书
C.
测试前建议停用 β - 受体阻滞剂
D.
确定适应症、禁忌症
E.
心肺复苏急救设备和药物
【多选题】根据《合同法》规定,下列属于效力待定合同的是:
A.
某企业的法定代表人超越权限与善意第三人订立的合同
B.
限制民事行为能力人与他人订立的买卖合同
C.
无代理权人以他人名义订立的合同
D.
无处分权人处分他人财产的合同
E.
恶意串通损害国家利益的合同
【单选题】青霉素皮内试验结果,哪项为阳性反应( )
A.
皮丘无改变
B.
全身无自觉症状
C.
皮丘周围无红肿
D.
皮丘红肿,直径大于1cm
【单选题】青霉素皮内试验结果,哪项为阳性反应:( )
A.
皮丘无改变
B.
无自觉症状
C.
丘疹大于1cm
D.
周围无红肿
E.
丘疹小于1cm
相关题目: