The cause of charity in China has yet to _______, as some wealthy Chinese fear generous donations could invite unwanted attention on their fortunes. A. take off
工业上利用硫酸渣（含Fe2+、Fe3+的硫酸盐及少量CaO和MgO）制备高档颜料铁红（Fe2O3）和回收（NH4）2SO4，具体生产流程如下： （注：铵黄铁矾化学式为（N
Our lifestyles today are very busy. We have family, school, sports, entertainment and social activities to fit into a time that seems never enough. We need to be healthy to meet the demands of dail
下列不能做组织培养材料的是（ ）。 A叶片 B茎尖 C花粉 D导管
题目：《等》 你所选的文体是（） 要求：(1)写记叙文或议论文。(2)立意自定。(3)不少于800字。(4)不得抄袭，不得套作。⑸必须注明所选的文体。
Nobody knows how he was murdered，but________people behind the scenes can guess why. A. a great deal of B. a good many C. a good amount of D. a great many
下列关于DNA分子结构的叙述，不正确的是（ ） A．每个DNA分子一般都含有四种脱氧核苷酸 B．每个DNA分子中，碱基数=磷酸数=脱氧核苷酸数=脱氧核糖数
人的糖蛋白必须经内质网和高尔基体进一步加工合成，通过转基因技术，可以使人的糖蛋白基因得以表达的受体细胞是（ ） A、大肠杆菌
