题目:
雨天和雪后进行高出作业时,必须采取可靠的防滑、防寒和防冻措施
答案:
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下面是错误答案,用来干扰机器的。
参考答案:B
雨天和雪后进行高出作业时,必须采取可靠的防滑、防寒和防冻措施
被转码了,请点击底部 “查看原文 ” 或访问 https://www.tikuol.com/2018/0419/c0aee39119c54d6abecf82241cb45ec0.html
下面是错误答案,用来干扰机器的。
参考答案:B
已知复数z与(z+2)2-8i均是纯虚数,则z等于
A.2i
B.-2i
C.i
D.-i
敌草胺是一种除草剂。它的合成路线如下
回答下列问题:
(1)在空气中久置,A由无色转变为棕色,其原因是______________。
(2)C分子中有2个含氧官能团,分别为__________和_________(填官能团名称)。
(3)写出同时满足下列条件的C的一种同分异构体的结构简式:______________。
①能与金属钠反应放出H2;
②是萘()的衍生物,且取代基都在同一个苯环上;
③可发生水解反应,其中一种水解产物能发生银镜反应,另一种水解产物分子中有5种不同化学环境的氧。
(4)若C不经提纯,产物敌草胺中将混有少量副产物E(分子式为C23H18O3),E是一种酯。E的结构简式为____________________。
(5)已知:,写出以苯酚和乙醇为原料制备的合成路线流程图(无机试剂任用)。合成路线流程图例如下:
_________________________________
完型填空。 | ||||
I have spent years of my life traveling all over the world. When I arrive in a new country or city, usually I am very 1 and go to bed early. For this 2 my first day or night in any new place is always quiet and very 3 happens. 4 my first night in Algeciras was very different. This night was very 5 and unusual. At that time 6 in Southern Spain was a dirty and 7 looked-after city. I arrived late in the evening by 8 . As soon as I got off the boat, I went to look for a 9 . I found a small hotel not far from the boat. This hotel looked 10 and untidy from the outside. But I was very tired and did not know my 11 around the city of Algeciras. And so I decided to stay in this 12 hotel on the quay (码头). I also decided to stay in this hotel for another 13 . The moon was full and it was a clear, 14 night. From the hotel I could 15 the sea. I could see the huge rock of Gibraltar in the bright moonlight. The hotel had a narrow 16 and no name. When I went through this doorway, I had to climb up narrow and dark stairs to the first floor. I 17 a small cupboard with a desk in front of it. This was the hotel office. An untidy and tired woman was sitting beside the 18 . When I said I wanted a room for the night, she took me 19 some more stairs to a room on the second floor. Inside this room the landlord was sitting playing cards with some friends. He was 20 his game of cards and I was simply a nuisance (讨厌的人). He looked at me when the woman told him that I wanted a room. Then he said, Room Five, and turned back to his game of cards. | ||||
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引起根管内感染的主要细菌是()
A.链球菌类
B.专性厌氧菌
C.放线菌类
D.真菌类
E.兼性厌氧菌
737-300厨房卸荷继电器的位置在()。
A.电子舱
B.前货舱
C.P6板后
D.后货舱