A:做实验并观察实验现象→分析、解释,得出结论
B:观察溴的外观性质→做实验并观察实验现象→分析、解释,得出结论
C:观察溴的外观性质→预测溴的化学性质→做实验并观察实验现象→分析、解释,得出结论
D:预测溴的性质→做实验并观察实验现象→分析、解释,得出结论→观察溴的外观性质
碑文是指在竖石上专为刻碑而作的文字,如图是东汉《张迁碑》碑文拓片(部分).观察拓片文字,由此推断出该书法艺术是( )
下列关于相关反应的叙述错误的是( )
Dear students,
An English lecture will be held in the lecture hall from 4 to 6 p.m. On March 7. It will be given by Professor Li Ping from Peking University. The topic is “How to learn English well”. You may take notes if you like. And you may ask questions about learning English during the break. If you are interested, please attend the lecture on time.
English Club
March 2, 2017
Dear all students,
March 12 is Tree Planting Day. We have decided to go and plant trees that day. All the students in our school are supposed to take part in this activity. We are going to gather at the school gate at 7:00 tomorrow morning. And then, we will take our school bus to West Hill. Please don't be late or absent. Pay attention to safety during the planting. Please wear sports shoes as well.
Student Union
March 11, 2017
Found
A jacket was found on the playground on the afternoon of March 1. It is a new black jacket. There is a key in the pocket. The owner can come to Room 201, Building 3 to get it.
Li Hua
Class 3, Grade 8
“全碳气凝胶”固体材料是我国科学家研制的迄今为止世界上最“轻”的材料,其坚固耐用程度不亚于高强度的合金材料,能承受1400℃的高温,而密度只有3kg/m3。己知某飞机采用密度为6×103 kg/m3高强度合金材料制造,需要合金1.2×105kg,若采用“全碳气凝胶”代替合金材料,需要“全碳气凝胶”的质量( )