【单选题】有关研究表明,3~4岁幼儿的词汇量为1730个,4~5岁幼儿为2853个,5~6岁为3562个,由此结果可看出,()是幼儿词汇量增长的活跃期。
【判断题】硅酸盐水泥熟料中硅酸钙矿物不小于66%。
【单选题】In his______to the Congress, Obama pivoted his administration from focusing on stopping the economic decline to recovery through reinvention.
【单选题】在引入线程的操作系统中,资源分配的基本单位是____。