皮皮学，免费搜题
登录
搜题
【单选题】
下列有关合金的说法中正确的是A.
青铜、硬铝和不锈钢都属于合金
B.
铝合金是用量最大、用途最广的合金
C.
铝合金是一种纯净物，它比纯铝的硬度大
D.
Na－K合金的熔点介于Na和K熔点之间
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
【单选题】Helmholtz free energy is a thermodynamic potential that measures the useful work obtainable from a closed thermodynamic system at:
A.
A constant temperature and pressure
B.
A constant temperature and volume
C.
A variable pressure and variable temperature
D.
None the above
【简答题】The work obtainable equals that expended. (定语词序调整)
【简答题】材料1：华西集团董事长吴仁宝认为，中国加入世贸后，国内国际市场形势将有较大变化，为此华西的经济要进行新的调整。华西的竞争对手主要来自“两大”，即大的国有企业和大的外贸企业、外商独资企业。加入世贸之后，国外的大公司、大企业将不断涌入中国，这些企业具有技术含量高、产品档次高、公司信誉高等优势，这对国内企业冲击很大。
材料2：红豆集团早在1993年就开始做好迎接入世的准备。目前该集团已在54个国家和地区...
【多选题】Marshall Hall's five principles (1831) for animal welfare are:
A.
An experiment should never be performed, if the necessary information could be obtained by observations. No experiment should be performed without a defined, obtainable, objective.
B.
Scientists should be well informed about the work of their predecessors and peers in order to avoid unnecessary repetition of an experiment.
C.
Justifiable experiments should be carried out with the least possible infliction of suffering (often through the use of lower, less sentient animals).
D.
Every experiment should be performed under circumstances that would provide the clearest possible results, thereby diminishing the need for repetition of experiments.
相关题目：