题型:选择题 — This returned scientist has become one of the top experts in his field. — Yes, I know him very well. He once _____ in South America with wild animals for eight years.A. has worked B. worked C. had worked D. has been working 查看答案
题型:选择题 配制质量分数为20%的食盐水30g,需要食盐的质量和水的体积(水的密度为1g/mL)分别为( )A.6g,24mLB.0.6g,29.4mLC.20g,80mLD.20g,100mL 查看答案
题型:问答题 案例分析题 H局运维部反映,最近有多个用户投诉手机信号波动问题。现在,公司派你去解决H局信号波动的问题,请根据以下了解的三种情况,对问题进行分析。用户反映在他没打电话(空闲状态),并保持静止不动的情况下,手机上的信号格数经常变化,甚至偶尔出现信号从5格降到2格,又从2格增加到5格的现象。则可能的原因有那些? 查看答案