玉米丝黑穗病和玉米瘤黑粉病在症状和侵染循环上有何区别? 发布时间:2017-10-19 22:03 │ 来源:www.tikuol.com 题型:问答题 简答题 问题: 玉米丝黑穗病和玉米瘤黑粉病在症状和侵染循环上有何区别?
题型:问答题 简答题 (4分)分类归纳是化学学习的重要方法。下面是某同学对所学物质的分类归纳,请仔细分析并回答下列问题:(1)写出C组物质所属的类别 。(2)在分类所列举的物质中,有一种物质归类错误,这种物质是 。(3)选择分类物质中的一种,写出一个有单质生成的分解反应的化学方程式(条件所需物质不受所列物质限制) 。 查看答案
题型:问答题 简答题 王鹏同学用石灰石(杂质溶于水,也不与酸反应)和稀盐酸反应制取二氧化碳后,决定用反应后的废液来测定一瓶Na2CO3溶液的溶质质量分数.他将废液过滤,然后向滤液中慢慢滴加Na2CO3溶液,加入Na2CO3溶液的质量与生成沉淀质量的关系到如图所示.(1)在加入Na2CO3溶液的过程中,开始一段没有沉淀生成,说明滤液中的溶质除含有CaCl2外,还含有______.(2)计算Na2CO3溶液的溶质质量分数.(3)若实验测得的Na2CO3溶液的溶质质量分数比其实际值偏大,原因是______. 查看答案
题型:问答题 简答题 APPLICATION FOR EMPLOYMENT (求职申请)Name Harry SmithAddress 4224 Maple Avenue Oakland, CaliforniaTelephone number 555-1660 Work ExperienceCompanyAmes BookstoreGreenfield High SchoolPositionBook sellerEnglish teacherWork I didSold booksTaught EnglishDates I worked1997—19992000—2009Yearly pay$ 10,400$ 27,500Reason for leavingGot a job teaching in MassachusettsGot a job in California小题1: What did Harry Smith do in 2001?A.An English teacher.B.A book seller.C.A secretary.D.A gatekeeper.小题2:If you want to know more about Harry Smith, you can call ________.A.4224-1660B.555-1666C.4224-1666D.555-1660小题3:Where did Harry Smith work in 2009?A. In New York. B. In California. C. In Massachusetts. D. In Washington D.C.小题4: In 2002, the yearly pay Harry Smith got from his work was ________.A.$20,800B.$ 10,400C.$ 27,500D.$55,000小题5:Harry Smith left Ames Bookstore to work in ________ in Massachusetts.A.a high schoolB.a bookstoreC.a factoryD.a company 查看答案